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)". Your task is to determine which category of federal government agencies and activities best describes this litigant.

Opinion:
COMMISSIONER OF INTERNAL REVENUE v. WIDENER (three cases).
Circuit Court of Appeals, Third Circuit
June 20, 1929.
Nos. 4001, 4002, 4003.
Mabel Walker Willebrandt, Asst. Atty. Gen., and John Vaughan Groner and Bar-ham R. Gary, both of Washington, D. C. (C. M. Charest, General Counsel, and Shelby S. Faulkner, Sp. Atty. Bureau of Internal Revenue, both of Washington, D. C., of counsel), for appellant.
Ellis Ames Ballard, William R. Spofford, and Schoffleld Andrews, all of Philadelphia, Pa. (Ballard, Spahr, Andrews & Ingersoll, of Philadelphia, Pa., of counsel), for appellees.
Before BUFFINGTON and WOOLLEY, Circuit Judges, and THOMSON, District Judge.
BUFFINGTON, Circuit Judge.
These cases present the question whether the Board of Tax Appeals erred in holding, as it did, that the racing stables of these taxpayers were operated as a “business,” or a “transaction entered into for profit,” within the meaning of the Revenue Acts of 1918 and 1921 (40 Stat. 1057, 42 Stat. 227). The Board of Tax Appeals held they were, and allowed reductions for losses thereby sustained. Thereupon the Commissioner took this appeal. The facts are not in dispute, and the warrant for the conclusions drawn therefrom by the Board are so fully and satisfactorily set forth in the record as to make a restatement by this court unnecessary.
Finding no error, judgment of the Tax Board is affirmed.

Question: This question concerns the first listed appellant. The nature of this litigant falls into the category "federal government (including DC)". Which category of federal government agencies and activities best describes this litigant?

Choices:
cabinet level department
courts or legislative
agency whose first word is "federal"
other agency, beginning with "A" thru "E"
other agency, beginning with "F" thru "N"
other agency, beginning with "O" thru "R"
other agency, beginning with "S" thru "Z"
Distric of Columbia
other, not listed, not able to classify

Answer: 4