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:
Howard STEPHENS, Jr., Joe Louis Barnett, Joseph J. Carter, and Ronald Moody, Petitioners, v. NATIONAL LABOR RELATIONS BOARD, Respondent, and Local 1838, International Longshoremen’s Association, AFL-CIO, and Charles Rogers, its President, Intervenors.
No. 14153.
United States Court of Appeals, Fourth Circuit.
Argued Oct. 6, 1970.
Decided Oct. 12, 1970.
Ellison D. Smith, IV, Columbia, S. C. (Smith & Smith, Columbia, S. C., on the brief), for petitioners.
Ira M. Goldberg, Atty., N. L. R. B. (Arnold Ordman, General Counsel, Dominick L. Manoli, Asst. General Counsel, Marcel Mallet-Prevost, Asst. General Counsel, and Eugene B. Granof, Atty., N. L. R. B., on the brief), for respondent.
Seymour M. Teach, Norfolk, Va. (Breit, Rutter, Cohen, Ermlich & Friedman, Norfolk, Va., on the brief), for inter-venors.
Before BRYAN, WINTER and CRAVEN, Circuit Judges.
PER CURIAM:
On petition to review and set aside the Board’s order dismissing a complaint that the Union had engaged in unfair labor practices in violation of §§ 8(b) (1) (A) and 8(b) (2) of the Act, we find substantial evidence in the record as a whole to support the Board’s conclusion that the Union did not violate the Act in the particulars charged. We decline to set aside the Board’s order.
Petition denied.

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: 9