<Page>

             ALLMERICA FINANCIAL LIFE INSURANCE AND ANNUITY COMPANY

                       ENHANCED DEATH BENEFIT "EDB" RIDER

OVERVIEW: This Enhanced Death Benefit Rider ("Rider") is an optional rider the
Owner has selected. It provides a Death Benefit with a guarantee that increases
if the Accumulated Value reaches certain values.

APPLICABILITY: This Rider is made a part of the contract to which it is attached
and is effective on the issue date.

DEFINITION(S): Current Breakthrough Value: On the issue date, it is equal to the
Initial Payment. The Current Breakthrough Value increases each time the
Accumulated Value grows to an amount equal to or greater than the Target
Breakthrough Value. Immediately after such growth in the Accumulated Value, the
Current Breakthrough Value will be equal to the Target Breakthrough Value
immediately prior to such growth. This value is increased by subsequent Payments
and proportionately reduced by subsequent withdrawals (see Payments and
Withdrawals, below).

Target Breakthrough Value: It is equal to [115%] of the Current Breakthrough
Value.

BENEFIT: The "Death Benefit" section of the "DEATH BENEFIT" provision is
replaced by the following:

I.   If an Owner, or an Annuitant if the Owner is a non-natural person, dies
     before the Annuity Date and before his/her [90th] birthday, the Death
     Benefit will be the greater of:

     (a)  the Accumulated Value on the date on which both the death certificate
          and all necessary claim paperwork, as determined by the Company, have
          been received at the Principal Office, increased for any positive
          Market Value Adjustment ("MVA"), if applicable; or

     (b)  the Current Breakthrough Value on the date of death, increased for
          subsequent Payments, and proportionately reduced for subsequent
          withdrawals.

II.  If an Owner, or an Annuitant if the Owner is a non-natural person, dies
     before the Annuity Date and on or after his/her [90th] birthday, the Death
     Benefit will be the greatest of:

     (a)  the Accumulated Value on the date on which both the death certificate
          and all necessary claim paperwork, as determined by the Company, have
          been received at the Principal Office, increased for any positive MVA,
          if applicable;

     (b)  the Current Breakthrough Value on the deceased's [90th] birthday,
          increased for subsequent Payments, and proportionately reduced for
          subsequent withdrawals; and

     (c)  the Accumulated Value, increased for any positive MVA, if applicable,
          on the deceased's [90th] birthday, increased for subsequent Payments,
          and proportionately reduced for subsequent withdrawals.

PAYMENTS AND WITHDRAWALS:

I.   When a Payment is made, on the Effective Valuation Date of the Payment:

     (a)  the Current Breakthrough Value will increase by an amount equal to the
          Payment, and

     (b)  the Target Breakthrough Value will increase to an amount equal to
          [115%] of the Current Breakthrough Value immediately after such
          Payment.


<Page>

II.  When a withdrawal is taken, on the Effective Valuation Date of the
     withdrawal:

     (a)  the Current Breakthrough Value will be proportionately reduced, and

     (b)  the Target Breakthrough Value will decrease to an amount equal to
          [115%] of the Current Breakthrough Value immediately after such
          withdrawal.

PROPORTIONATE REDUCTION: Sections I(b), II(b) and II(c) of the "Benefit"
provision and Section II(a) of the "Payments and Withdrawals" provision are
proportionately reduced by withdrawals. This proportionate reduction is
calculated by multiplying the Section I(b), II(b) or II(c) value or the Current
Breakthrough Value, whichever is applicable, determined immediately prior to the
withdrawal by the following:

                            Amount of the withdrawal
                            ------------------------
                    Accumulated Value determined immediately
                             prior to the withdrawal

CHARGE FOR BENEFIT: [While this Rider is in effect, the Company will assess an
EDB Charge equal to an annual percentage rate of .25% on a contract monthly
basis. On the last day of each contract month, the monthly charge is deducted
Pro Rata and is equal to 1/12th of the EDB Charge multiplied by the Accumulated
Value of the contract on that date.] The EDB Charge only applies during the
Accumulation Phase.

TERMINATION: This Rider will terminate on the earliest of the following:

     (a)  the Annuity Date;

     (b)  the date the Company determines a Death Benefit is payable and the
          contract is not continued under a spousal takeover; or

     (c)  surrender of the contract.

                    Signed for the Company at Dover, Delaware


         [/s/ Mark A. Hug]                      [/s/ Charles F. Cronin]

            President                                 Secretary