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.

COMMISSIONER OF INTERNAL REVENUE, Petitioner, v. SHERWOOD SWAN AND COMPANY, Ltd., et al., Respondents.
No. 19627.
United States Court of Appeals Ninth Circuit.
Nov. 8, 1965.
Louis F. Oberdorfer, Asst. Atty. Gen., Lee A. Jackson, Harry Baum, Edward L. Rogers, Attys., Dept, of Justice, Washington, D. C., for petitioner.
James F. Crafts, Jr., Orrick, Dahlquist, Herrington & Sutcliffe, San Francisco, Cal., for respondent.
Before HAMLEY, HAMLIN and DUNIWAY, Circuit Judges.
HAMLEY and DUNIWAY,
Circuit Judges:
The decision of The Tax Court is affirmed for the reasons stated by that court in its opinion reported at 42 T.C. 299.

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?
A. Food & Drug Administration
B. General Services Administration
C. Government Accounting Office (GAO)
D. Health Care Financing Administration
E. Immigration & Naturalization Service (includes border patrol)
F. Internal Revenue Service (IRS)
G. Interstate Commerce Commission
H. Merit Systems Protection Board
I. National Credit Union Association
J. National Labor Relations Board
K. Nuclear Regulatory Commission
Answer: