Execution Copy

FOURTH AMENDMENT TO PURCHASE AGREEMENT

THIS FOURTH AMENDMENT TO PURCHASE AGREEMENT (the "Amendment") is made as
of  December 3, 2008, by and between (i) DTC PARTNERS, LLC, a Virginia limited
liability company (“Seller”), and (ii) NATIONAL RURAL UTILITIES COOPERATIVE
FINANCE CORPORATION, a District of Columbia cooperative
association  (“Purchaser”).

RECITALS:

A.           Seller and Purchaser entered into that certain Purchase Agreement
dated May 2, 2008 (the “Original Agreement”), as amended by that certain First
Amendment to Purchase Agreement dated June 30, 2008, as further amended by that
certain Second Amendment to Purchase Agreement dated July 29, 2008, and as
further amended by a Third Amendment to Purchase Agreement dated August 25, 2008
(the “Third Amendment”, and collectively, the “Purchase Agreement”), by which
Seller agreed to sell and Purchaser agreed to purchase either the Option 1
Parcel (as defined in the Agreement) or the Option 2 Parcel (as defined in the
Agreement), constituting a part of approximately 189.51 acres of unimproved land
owned by Seller located near the intersection of Route 7 and Route 28 in Loudoun
County, Virginia comprising a portion of the "Dulles Town Center Project" and
known as Tax Map 80-102A (GPIN No. ###-##-####), all as more particularly
described in the Agreement.

B.           Seller and Purchaser desire to amend the Agreement to reflect their
agreement modifying the terms of and the corresponding form of the Repurchase
Option Agreement, among other things, as more fully set forth in this Amendment.

 
AGREEMENT:

NOW, THEREFORE, in consideration of the mutual rights and obligations hereunder,
Seller and Purchaser hereby agree as follows:

1.
Purchase Agreement.   The parties agree that the Purchase Agreement is in full
force and effect, unamended except as expressly set forth in this
Amendment.  All capitalized terms used in, and not otherwise defined in, this
Amendment shall have the meanings given them in the Purchase Agreement.

2.
Repurchase Option Agreement.  Seller and Purchaser agree that the Repurchase
Option Agreement shall be substantially in the form of the Repurchase Option
Agreement attached to this Amendment, (the “Repurchase Option Agreement”) and
that this form shall supersede the Repurchase Option Agreement attached as
Exhibit D to the Original Agreement.

 
3.
Preparation of Building Plans.  The timeframes for (i) the preparation of
Building Plans in Section 8(f) of the Purchase Agreement; (ii) the filing for
the Building Permit in

 

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Section 8(h) of the Purchase Agreement and (iii) for the issuance of the Notice
to Proceed for the construction of the office building in Section 10(b) are
hereby deleted.

 
4.
Construction Covenant.  If Seller timely delivers the Second Exercise Notice
pursuant to Section 4(a) of the Repurchase Option Agreement and if Purchaser
nullifies Seller’s exercise of the Second Option by causing the Construction
Condition to be satisfied, as permitted by Section 4(b) of the Repurchase Option
Agreement, Purchaser covenants and agrees with Seller that Purchaser shall
prosecute to substantial completion (as defined below) the work of constructing
the Century Boulevard Extension (as defined in the Purchase Agreement) and
constructing an office building containing at least 120,000 square feet of gross
floor area on the Property (as defined in the Purchase Agreement) in good faith,
with diligence and continuity, subject to delays incurred by Purchaser that have
the effect of delaying the performance of the construction work (other than an
obligation to pay a sum of money), but only to the extent that such delays are
caused by Force Majeure Events.  For purposes of this Amendment, the term “Force
Majeure Event” means any of the following events, regardless of where they occur
or their duration:  acts of nature (including hurricanes, typhoons, tornadoes,
cyclones, other severe storms, winds, lightning, floods, earthquakes, volcanic
eruptions, fires, explosions, disease, or epidemics); fires and explosions
caused wholly or in part by human agency; acts of war or armed conflict; riots
or other civil commotion; terrorism (including hijacking, sabotage, chemical or
biological events, nuclear events, disease-related events, bombing, murder,
assault and kidnapping), or the threat thereof; strikes or similar labor
disturbances; embargoes or blockades; shortage of critical materials or
supplies; action or inaction of governmental authorities which have an impact
upon the performance of the construction work (including the revocation or
refusal to grant licenses or permits, where such revocation or refusal is not
due to Purchaser’s actions or inaction); and any other event beyond Purchaser’s
reasonable control, excluding, however, general economic and/or market
conditions not caused by any of the events described above.  All capitalized
terms used in this Section that are not otherwise defined in this Section shall
have the meanings assigned to those terms in the Repurchase Option
Agreement.  Purchaser’s obligations under this Section shall survive the Closing
under the Purchase Agreement and the termination of the Repurchase Option
Agreement. Substantial completion of the Century Boulevard Extension means the
road is open to traffic and any associated landscaping is
installed.  Substantial completion of the office building means the exterior of
the building is completed and all parking areas, travelways and landscaping has
been installed, but does not require the completion of interior build-out.

 
5.
Joinder of Mortgagee.   Paragraph 4 of the Third Amendment to Purchase Agreement
dated August 25, 2008, shall not apply if the Wachovia loan secured by the deed
of trust encumbering the Overall Property is paid off and released in connection
with the Closing under the Purchase Agreement.

6.
Ratification.  Except as specifically modified herein, all terms and conditions
of the Purchase Agreement are hereby ratified by the parties hereto and shall
remain in full force and effect.  In the event that any terms of this Amendment
shall conflict with the terms of the Purchase Agreement, the terms of this
Amendment shall prevail.  All references herein to the “Purchase Agreement”
shall mean the Purchase Agreement as amended by this Amendment.  This Amendment
may be executed in counterparts and/or with counterpart signature pages, all of
which together shall constitute a single agreement.

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IN WITNESS WHEREOF, the undersigned parties have executed this Amendment as of
the day and year first above stated.

 
SELLER
 
DTC PARTNERS, LLC

By:            Lerner Enterprises, LLC, its
           Authorized Member
 
By:  /s/ MARK D. LERNER
 
Name: Mark D. Lerner
 
Title:  Manager
 
Date of Signing:  December 4, 2008
 

 
PURCHASER
 
NATIONAL RURAL UTILITIES COOPERATIVE FINANCE CORPORATION

    By:  /s/  JOHN T. EVANS
Name: John T. Evans
Title: Senior Vice President
 
Date of Signing:  December 3, 2008
 
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EXHIBIT
 
 
[Form of Repurchase Option Agreement]
 

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DTC Draft 12/2/2008(version 4)

REPURCHASE OPTION AGREEMENT

THIS AGREEMENT is made and entered into as of December ____, 2008 (the
“Effective Date”) between (i) NATIONAL RURAL UTILITIES COOPERATIVE FINANCE
CORPORATION (“CFC”), a District of Columbia cooperative association, and (ii)
DTC PARTNERS, LLC (“DTC”), a Virginia limited liability company.

R E C I T A L S

A.           Contemporaneously herewith CFC has purchased from DTC that certain
parcel of land (the “CFC Tract”) described in Exhibit A attached hereto,
pursuant to a Purchase Agreement dated as of May 2, 2008, as amended, between
DTC, as Seller, and CFC, as Purchaser (the “Purchase Agreement”).  All
capitalized terms used in this Agreement that are not specifically defined in
this Agreement have the meanings assigned to those terms in the Purchase
Agreement.

B.           CFC has agreed to grant to DTC an option to purchase the CFC Tract
and all improvements and appurtenances thereon but exclusive of movable
equipment and fixtures, inventory, signs and other personal property (the
“Property”) upon certain conditions.

NOW THEREFORE, in consideration of the premises, and good and valuable
consideration given and the receipt of which is hereby acknowledged, the parties
agree as follows:

1.           OPTION EVENT

DTC shall have the option (the “First Option”) to purchase the Property for the
purchase price provided in Section 2 during the time period provided in Section
3(a) and otherwise on the terms of this Agreement, if the Construction Condition
(defined below) does not occur on or before November 30, 2010.  If (i) DTC does
not timely exercise the First Option, or (ii) DTC timely exercises the First
Option, but CFC timely nullifies DTC’s exercise of the First Option by paying
the Extension Payment pursuant to Section 3(b), then, in either such event, DTC
shall have the option (the “Second Option” to purchase the Property for the
purchase price provided in Section 2 during the time period provided in Section
4(a) and otherwise on the terms of this Agreement, if the Construction Condition
does not occur on or before November 30, 2014.  For purposes of this Agreement,
the term “Construction Condition ” means that CFC has commenced the construction
of an office building on the CFC Tract that will contain at least 120,000 square
feet of gross floor area, as evidenced by (i) the issuance by CFC to its general
contractor of a notice to proceed authorizing such general contractor to
commence construction of such office building, (ii) the delivery by CFC to DTC
of a copy of the notice to proceed referred to in clause (i),(iii) the posting
of all required bonds with Loudoun County, and (iv) the site contractor’s good
faith commencement of the work of grading and excavation for the site work
commencing at the terminus of the Century Boulevard Extension (as defined in the
Purchase Agreement), including sequentially the site work for the office
building and including sequentially the construction of such office
building.  For all purposes of this Agreement, the term “Option” means the First
Option or the Second Option.

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2.           PURCHASE PRICE

The purchase price of the Property pursuant to the Option shall be an amount
equal to the sum of the Purchase Price of the Property paid by CFC to DTC
pursuant to the Purchase Agreement, reduced by (i) the Virginia grantor’s tax
paid by DTC, as Seller, in connection with the original sale of the Property to
CFC pursuant to the Purchase Agreement, and (ii) the Adjustment Amount (defined
below).  For purposes of this Section 2, the term “Adjustment Amount” means the
excess of (i) $3,500,000, over (ii) the Extension Payment, if any, paid by CFC
to DTC pursuant to Section 3(b) below.
 
3.           EXERCISE OF THE FIRST OPTION

(a)           DTC may exercise the First Option by delivering written notice of
the exercise of the First Option (the “First Exercise Notice”) to CFC at any
during the period beginning on December 1, 2010 and ending on December 15,
2010.  The First Exercise Notice must include an earnest money deposit of
$250,000 in cash or a certified check made payable to CFC.  CFC’s receipt of the
First Exercise Notice and the earnest money deposit shall immediately create an
effective and binding contract by CFC to sell to DTC, and by DTC to purchase
from CFC, the Property on the terms and conditions set forth herein.  If DTC
does not exercise the First Option within the time or in the manner specified in
this Section, the First Option shall lapse and shall be of no further force or
effect.  If, after delivery of the First Exercise Notice, DTC does not close the
transaction in accordance with the terms hereof, the $250,000 earnest money
deposit shall be retained by CFC, as consideration for the grant of the First
Option and for withholding the Property from the marketplace, and the First
Option shall terminate.

(b)           If DTC timely delivers the First Exercise Notice, CFC shall have
the right, within five (5) Business Days after receipt of the First Exercise
Notice, to nullify DTC’s exercise of the First Option by paying to DTC, within
the period of five (5) Business Days, an amount equal to $2,500,000 (the
“Extension Payment”).

(c)           If CFC timely pays the Extension Payment, (i) DTC’s exercise of
the First Option shall be deemed to have been rescinded, (ii) CFC shall return
to DTC, concurrently with the payment of the Extension Payment, the $250,000
earnest money deposit paid by DTC at the time it delivered the First Exercise
Notice, which is deemed rescinded pursuant to clause (i), and (iii) DTC shall
have the right to exercise the Second Option in accordance with the provisions
of Section 4.

4.           EXERCISE OF SECOND OPTION

(a)           If DTC has the right to exercise the Second Option pursuant to
Section 3(c), DTC may exercise the Second Option by delivering written notice of
the exercise of the Second Option (the “Second Exercise Notice”) to CFC at any
time during the period beginning on December 1, 2011 and ending on December 15,
2014.  The Second Exercise Notice must include an earnest money deposit of
$250,000 in cash or a certified check made payable to CFC.  CFC’s receipt of the
Second Exercise Notice and the earnest money
 
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deposit shall immediately create an effective and binding contract by CFC to
sell to DTC, and by DTC to purchase from CFC, the Property on the terms and
conditions set forth herein.  If DTC does not exercise the Second Option within
the time or in the manner specified in this Section, the Second Option shall
lapse and shall be of no further force or effect.  If, after delivery of the
Second Exercise Notice, DTC does not close the transaction in accordance with
the terms hereof, the $250,000 earnest money deposit shall be retained by CFC,
as consideration for the grant of the Second Option and for withholding the
Property from the marketplace, and the Second Option shall terminate.

(b)           If DTC timely delivers the Second Exercise Notice, CFC shall have
the right, within ninety (90) days after receipt of the Second Exercise Notice,
to nullify DTC’s exercise of the Second Option by causing the Construction
Condition to be satisfied.

(c)           If the Construction Condition is satisfied, (i) DTC’s exercise of
the Second Option shall be deemed to have been rescinded, (ii) CFC shall return
to DTC, within five (5) Business Days after the Construction Condition is
satisfied, the $250,000 earnest money deposit paid by DTC at the time it
delivered the Second Exercise Notice, which is deemed rescinded pursuant to
clause (i), and (iii) the Second Option shall lapse.

5.           CLOSING

If DTC timely delivers the First Exercise Notice and pays the deposit to CFC
pursuant to Section 3(a), DTC’s purchase of the Property shall be consummated
within thirty (30) days after delivery of the First Exercise Notice.  If DTC’s
exercise of the First Option is deemed rescinded pursuant to Section 3(c), and
if DTC timely delivers the Second Exercise Notice and pays the deposit to CFC
pursuant to Section 4(a), DTC’s purchase of the Property shall be consummated
within thirty (30) days after the expiration of the 90-day period referred to in
Section 4(b).  The closing shall be conducted through an escrow established at
Commercial Title Group, Inc., 8605 Westwood Center Drive, Suite 200, Vienna,
Virginia 22182 (the “Escrow Agent”).  The purchase price shall be payable in
immediately available funds at the closing.  The Property shall be conveyed in
its "as is" condition.  Title to the Property shall be conveyed by CFC to DTC by
special warranty deed, subject only to (i) the lien of current real estate taxes
not yet due and payable, (ii) the Permitted Exceptions (as defined in the
Purchase Agreement), (iii) the exceptions to title created by the Lot Creation
Document and the documents signed and delivered in connection with the Closing
under the Purchase Agreement, and (iv) the matters shown by the survey, if any,
of the Property obtained by CFC in connection with its original purchase of the
Property.  Any mortgage or liens securing obligations for the payment of money
encumbering the Property shall be discharged from the purchase price proceeds
payable by DTC hereunder.  Current real property taxes and installments of
special assessments shall be prorated as of the date of closing.  CFC shall bear
the cost of the Virginia grantor’s tax on the deed and all other State and
County transfer and recordation taxes, and all other closing costs, including
escrow fees.

6.           NOTICES.

Each notice, request, demand, consent, approval or other communication
(hereafter in this Section referred to collectively as “notices” and referred to
singly as a “notice”) which DTC
 
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or CFC is required or permitted to give to the other party pursuant to this
Agreement shall be in writing and shall be delivered personally, by facsimile
transmission or by recognized overnight national courier service (such as
Federal Express) (i) if to DTC to the attention of Arthur N. Fuccillo, Lerner
Enterprises, LLC, 2000 Tower Oaks Boulevard, Eighth Floor, Rockville, Maryland
20852 (FAX: (301) 692-2626, with a copy to Mark D. Lerner, 2000 Tower Oaks
Boulevard, Eighth Floor, Rockville, Maryland 20852 (FAX: (301) 692-2626, or (ii)
if to CFC, to the attention of Joseph Siekierski, National Rural Utilities
Cooperative Finance Corporation, 2201 Cooperative Way, Herndon, Virginia 20171
(FAX: (703) 707-5033, with copies to General Counsel, National Rural Utilities
Cooperative Finance Corporation, 2201 Cooperative Way, Herndon, Virginia 20171
(FAX: (703) 709-6811, and to Benjamin F. Tompkins, Reed Smith, LLP, 3110
Fairview Park Drive, Suite 1400, Falls Church, Virginia 22042 (FAX: (703)
641-4340 or at any other address designated by either party by notice to the
other party pursuant to this Section.  Any notice delivered to a party’s
designated address by (a) personal delivery, (b) facsimile or (c) recognized
overnight national courier service shall be deemed to have been received by such
party at the time the notice is delivered to such party’s designated address.
 
7.           MISCELLANEOUS

(a)           Assignment.  The rights arising under this Agreement are personal
to DTC only and may not be assigned, whether collaterally or otherwise, in any
manner.

(b)           Termination.  This Agreement and the Option shall automatically
terminate upon the earliest to occur of (i) the satisfaction of the Construction
Condition, or (ii) the lapse of the Second Option accordance with Section
4(a).  Upon termination of this Agreement, DTC agrees to execute and deliver to
CFC, without cost to CFC, a termination (properly executed, acknowledged and in
recordable form) of all option rights contained in this Agreement and a release
of any interest of DTC in the Property arising out of this Agreement; provided
however, that the absence of such an instrument shall not affect the termination
of such right.

(c)           Binding Effect.  Subject to the provisions hereof regarding
assignment, this Agreement shall run with the land, shall bind the real estate
described herein and shall be binding upon and inure to the benefit of CFC and
DTC.

(d)           Amendment and/or Modification.  Neither this Agreement nor any
term or provision hereof may be changed, waived, discharged, amended or modified
orally, or in any manner other than by an instrument in writing signed by all of
the parties hereto.

(e)
Costs and Attorneys’ Fees.  If any party hereto shall bring any suit or other
action against another for relief, declaratory or otherwise, arising out of this
Agreement, the losing party shall pay the prevailing party’s reasonable costs
and expenses, including such sum as the Court may determine to be a reasonable
attorney’s fee.

(f)
Governing Law.  This Agreement shall be governed by, construed and enforced in
accordance with the laws of the state in which the Property is located, without
giving effect to principles and provisions thereof relating to conflict or
choice of laws.

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(g)
Documents.  Each party to this Agreement shall perform any and all acts and
execute and deliver any and all documents as may be necessary and proper under
the circumstances in order to accomplish the intents and purposes of this
Agreement and to carry out its provisions.

(h)           Entire Agreement; No Strict Construction.  This Agreement (and any
attached exhibits) contains the entire agreement and understanding of the
parties with respect to the entire subject matter hereof, and there are no
representations, inducements, promises or agreements, oral or otherwise, not
embodied herein.  Any and all prior discussions, negotiations, commitments and
understandings relating thereto are merged herein.  There are no conditions
precedent to the effectiveness of this Agreement other than as stated herein,
and there are no related collateral agreements existing between the parties that
are not referenced herein.  This Agreement shall not be construed strictly for
or against either DTC or CFC.

(i)
Counterparts.  This Agreement may be signed in counterparts, any one of which
shall be deemed to be an original and all of which, when taken together, shall
constitute one instrument.

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IN WITNESS WHEREOF, CFC and DTC have caused this Agreement to be executed
effective as of the day and year above referenced.

NATIONAL RURAL UTILITIES
COOPERATIVE FINANCE CORPORATION

By: _______________________________                                                     

Name: _____________________________                                                               

Title: ______________________________                                                               

COMMONWEALTH OF VIRGINIA                                 )
) ss.
COUNTY
OF                                                                         )

On this ______ day of ______________, 2008, before me, a Notary Public within
and for said County, personally appeared ______________________________ to me
personally known, being first by me duly sworn, did say that (s)he is the
__________________of NATIONAL RURAL UTILITIES COOPERATIVE FINANCE CORPORATION,
and that said instrument was signed on behalf of said corporation by authority
of its Board of Directors and ________________________ acknowledged said
instrument to be the free act and deed of said corporation.

__________________________________
Notary Public

My commission expires: ______________

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DTC PARTNERS, LLC

By Lerner Enterprises, LLC, its
Authorized Manager

By: ___________________________                                                     

Name: _________________________

Title: Manager ___________________

STATE OF MARYLAND                                   )
) ss.
COUNTY OF MONTGOMERY                          )

On this ______ day of ______________, 2008, before me, a Notary Public within
and for said County, personally appeared ______________________________ to me
personally known, being first by me duly sworn, did say that (s)he is the
Manager of Lerner Enterprises, LLC, the Authorized Manager of DTC PARTNERS, LLC,
and that said instrument was signed on behalf of said DTC PARTNERS, LLC, and
________________________ acknowledged said instrument to be the free act and
deed of said limited liability company.

____________________________________
Notary Public

My commission expires: ______________

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EXHIBIT A

Legal Description of CFC Tract