What follows is an opinion from a United States Court of Appeals.
Intervenors who participated as parties at the courts of appeals should be counted as either appellants or respondents when it can be determined whose position they supported. For example, if there were two plaintiffs who lost in district court, appealed, and were joined by four intervenors who also asked the court of appeals to reverse the district court, the number of appellants should be coded as six.
When coding the detailed nature of participants, use your personal knowledge about the participants, if you are completely confident of the accuracy of your knowledge, even if the specific information is not in the opinion. For example, if "IBM" is listed as the appellant it could be classified as "clearly national or international in scope" even if the opinion did not indicate the scope of the business. 

Your task concerns the first listed appellant. The nature of this litigant falls into the category "federal government (including DC)", specifically "other agency, beginning with "F" thru "N"". Your task is to determine which specific federal government agency best describes this litigant.

Opinion:
COMMISSIONER OF INTERNAL REVENUE v. LANGWELL REAL ESTATE CORPORATION.
No. 4403.
Circuit Court of Appeals, Seventh Circuit.
March 18, 1931.
G. A. Youngquist, Asst. Atty. Gen., and Sewall Key and John MaeC. Hudson, Sp. Assts. to Atty. Gen. (G. M. Charest, Gen. Counsel, Bureau of Internal Revenue, and Dean P. Kimball, Sp. Atty., Bureau of Internal Revenue, both of Washington, D. C., of counsel), for petitioner.
David J. Greenberg, of Chicago, 111., for respondent.
Before ALSCHULER, EVANS, and SPARKS, Circuit Judges.
EVANS, Circuit Judge
(after stating the facts as above).
We find it impossible to escape the conclusion that, upon the tenant’s release of its interest in said $50,000, respondent was enriched by that amount. Regulations 62, Treasury Department, article 50. It was relieved of its obligation to pay this amount to the tenant at the expiration of the lease. At the same time, and as a part of the same transaction, respondent released the tenant from its lease. Whether resp ondent suffered a loss by reason of the termination of the lease presents another issue, which is not covered by the findings of the Board of Tax Appeals. If respondent could have readily negotiated another lease with a responsible party, as favorable as the lease which was canceled, it suffered no loss. On the other hand, if it could not have negotiated such a lease, then it suffered a loss. The amount of such loss, if any, was the legitimate subject of proof. The actual execution of a new lease was not necessary to the determination, of this issue. The rental value of such property could be shown by oral testimony.
The Board of Tax Appeals stated:
“It seems clear that the petitioner assumed an obligation to pay the lessee $50,-000 in 1941 if all of the terms of the lease had been performed by the lessee during its life. This obligation, it is also apparent, did not stand alone, but was balanced by a corresponding obligation of the lessee. We are not able to say that they did not exactly balance, or, if not, in whose favor the scales were tipped. This being so, when the lessee and the petitioner then agreed to cancel the lease in June, 1923, it can not be said with any certainty whatever that the $50,000 obligation of the petitioner, contingent and uncertain as it was that return need ever be made, did not represent compensation to the petitioner for the loss sustained by it on the cancellation of the lease. If so, the amount would not be income to the petitioner.”
We think the Board was in error in assuming that a loss was sustained which offset the $50,000 gain. In the absence of proof sufficient to support a contrary finding by the Board of Tax Appeals, the finding of the Commissioner should have been sustained. Avery v. Commissioner (C. C. A.), 22 F.(2d) 6, 55 A. L. R. 1277. The record before us does not warrant our making a finding on this issue, nor is it necessary for us so- to do. 26 USCA § 1219; K. Coal Co. & D. Co. v. Commissioner (C. C. A.), 29 F.(2d) 559.
Under all of the circumstances, we think it would be promotive of justice in this instance to remand the case for further hearing. The taxpayer should be given the opportunity of offering evidence to show that it suffered a loss and also the extent of its loss. If the proof be sufficient to sustain a finding of the amount of such loss, that sum should 'be deducted from the said $50,009. If no such loss be established, then the sum of $50,000 should be included as part of the taxpayer’s income.
The order of the Board of Tax Appeals is reversed, with directions to proceed in accordance with the views herein expressed.

Question: This question concerns the first listed appellant. The nature of this litigant falls into the category "federal government (including DC)", specifically "other agency, beginning with "F" thru "N"". Which specific federal government agency best describes this litigant?

Choices:
Food & Drug Administration
General Services Administration
Government Accounting Office (GAO)
Health Care Financing Administration
Immigration & Naturalization Service (includes border patrol)
Internal Revenue Service (IRS)
Interstate Commerce Commission
Merit Systems Protection Board
National Credit Union Association
National Labor Relations Board
Nuclear Regulatory Commission

Answer: 5