What follows is an opinion from a United States Court of Appeals. Your task is to identify the federal agency (if any) whose decision was reviewed by the court of appeals. If there was no prior agency action, choose "not applicable".

Opinion:
In the Matter of the Application of Harry VISSERING.
Court of Appeals of District of Columbia.
Submitted January 11, 1928.
Decided March 5, 1928.
No. 2006.
Appeal from the Commissioner of Patents.
H. H. Benjamin, of Chicago, Ill., and J. T. Basseehes, of New York City, for appellant.
T. A. Hostetler, of Washington, D. C., for Com’r of Patents.
Before MARTIN, Chief Justice; VAN ORSDEL, Associate Justice; and SMITH, Judge of the United States Court of Customs Appeals.
VAN ORSDEL, Associate Justice.
This appeal is from the Commissioner of Patents rejecting appellant’s application for a patent for a car brake step described in the following claim: “1. A brake step adapted to be secured to a car body and having a shelf portion adapted to act as a rest for the foot and provided with an abutment portion comprising a plurality of continuous spaced pressed portions.”
The step is Z-shaped in cross section, and supported by V-shaped brackets. It is made of pressed sheet metal provided with corrugations on the upper surface to prevent the user from slipping.
In the opinions of the tribunals of the Patent Office, the construction upon which the patent is sought is clearly pointed out in three references relied upon, and from an examination of the prior art we agree with the Commissioner “that applicant has done no more than pick out one feature from one patent, another from another, and so on, and unite them in a single structure. The step possesses no new or improved function as a result of such assemblage of old features.”
The decision of the Commissioner is affirmed.

Question: What federal agency's decision was reviewed by the court of appeals?

Choices:
Benefits Review Board
Civil Aeronautics Board
Civil Service Commission
Federal Communications Commission
Federal Energy Regulatory Commission
Federal Power Commission
Federal Maritime Commission
Federal Trade Commission
Interstate Commerce Commission
National Labor Relations Board
Atomic Energy Commission
Nuclear Regulatory Commission
Securities & Exchange Commission
Other federal agency
Not ascertained or not applicable

Answer: 13