What follows is an opinion from a United States Court of Appeals.
Your task is to identify the issue in the case, that is, the social and/or political context of the litigation in which more purely legal issues are argued. Put somewhat differently, this field identifies the nature of the conflict between the litigants. The focus here is on the subject matter of the controversy rather than its legal basis.
Your task is to determine the specific issue in the case within the broad category of "economic activity and regulation - taxes, patents, copyright". 

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: What is the specific issue in the case within the general category of "economic activity and regulation - taxes, patents, copyright"?
A. state or local tax
B. federal taxation - individual income tax (includes taxes of individuals, fiduciaries, & estates)
C. federal tax - business income tax (includes corporate and parnership)
D. federal tax - excess profits
E. federal estate and gift tax
F. federal tax - other
G. patents
H. copyrights
I. trademarks
J. trade secrets, personal intellectual property
Answer: