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. CREWS and five other cases.
Nos. 1751-1756.
Circuit Court of Appeals, Tenth Circuit.
Dec. 11, 1939.
Ellis N. Slack, Sp. Asst, to the Atty. Gen. (James W. Morris, Asst. Atty. Gen., and J. Louis Monarch and Sewall Key, Sp. Assts. to the Atty. Gen., on the brief), for petitioner.
Albert L. McRill, of Oklahoma City, Okl., and Joseph D. Brady, of Los Angeles, Cal., for respondents.
Before PHILLIPS, BRATTON, and WILLIAMS/ Circuit Judges.
PHILLIPS, Circuit Judge.
These are petitions to review, consolidated in this court, decisions of the Board of Tax Appeals involving income taxes for the year 1930 on income derived from oil and gas wells.
These cases were before this court on a prior appeal. See Crews v. Commissioner, 10 Cir., 89 F.2d 412. They were reversed and remanded to the Board for further proceedings in accordance with the opinion.
In the original proceeding before the Board the parties stipulated that the cost of drilling, equipping, and operating the wells, and certain miscellaneous expenses incident to the production of oil and gas amounted to $849,544.37. At the hearing before the Board after the remand the parties stipulated that such sum was composed of the following items:
Operating Expense:
Production Expense....... $272,042.56
General Overhead Expense 31,107.34
Depreciation on Equipment 110,888.17
Total Operating Expense .............. $414,038.07
Development Expense (drilling costs) ..............'.. $387,982.80
Equipment ...... $158,411.67
Less: Depreciation sustained 110,888.17 47,523.50
Total ................ $849,544.37
The taxpayers deducted the development expenses and related depreciation in computing their taxable net income from the property for the year 1930.
The Board of Tax Appeals held that in computing the net income of the taxpayers from the property for the purpose of applying the 50 per cent limitation contained in Section 114(b) (3) of the Revenue Act of 1928, 26 U.S.C.A. § 114 note, the development expenses and related depreciation should not be deducted from the gross income from the property. This resulted in a depletion allowance of $333,700.42.
The Commissioner contends that in computing the depletion allowance the development expenses and related depreciation should be deducted in arriving at the net income from the property, and that the proper computation is as follows:
Gross Income from the property ................ $1,213,456.09
, Less: Operating and Development Expense..... 849,544.37
Net Income from the property ............ $ 363,911.72
50 per cent of the net income from the property equals........... $ 181,955.86
27% per cent of the gross income from the property equals .............. 333,700.42
The conflict of authority with respect to the meaning of the phrase “net income of the taxpayer (computed without allowance for depletion) from the property” in Section 114(b) (3) of the Revenue Act of 1928 has been set at rest by the decisions of the Supreme Court in Helvering, Commissioner v. Wilshire Oil Company, 60 S. Ct. 18, 84 L.Ed.-, and F. H. E. Oil Company v. Commissioner, 60 S.Ct. 26, 84 L.Ed. -, which 'sustain the contentions of the Commissioner in the instant cases. Hence, the proper depletion allowance is $181,955.-86.
The decisions are reversed and the causes are remanded, with instructions to redetermine the tax in accordance with this opinion.
See Ambassador Petroleum Co. v. Commissioner, 9 Cir., 81 F.2d 474; Commissioner v. Wilshire Oil Co., 9 Cir., 95 F.2d 971; Commissioner v. F. H. E. Oil Co., 5 Cir., 102 F.2d 596.

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