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:
SACO-LOWELL SHOPS, a Division of Maremont Corporation, Petitioner, v. NATIONAL LABOR RELATIONS BOARD, Respondent.
No. 12201.
United States Court of Appeals Fourth Circuit.
Argued Oct. 28, 1968.
Decided Nov. 14, 1968.
J. Frank Ogletree, Jr., Greenville, S. C. (Thompson, Ogletree & Haynsworth, Greenville, S. C., on brief) for petitioner.
John D. Burgoyne, Atty., N. L. R. B., (Arnold Ordman, Gen. Counsel, Dominick L. Manoli, Associate Gen. Counsel, and Marcel Mallet-Prevost, Asst. Gen. Counsel, on brief) for respondent.
Before BRYAN, WINTER and CRAVEN, Circuit Judges.
PER CURIAM:
The National Labor Relations Board found that Saco-Lowell Shops, a division of Maremont Corporation, had violated § 8(a) (1) of the Act, 29 U.S.C. § 158(a) (1), by the distribution of a handbook at its plant in Easley, South Carolina, containing a too rigid restriction upon the solicitation of employees to sign union authorization or membership cards, and had there also violated § 8(a) (3) of the Act, 29 U.S.C. § 158(a) (3), in discharging an employee because of his activities on behalf of the union. 169 N.L.R.B. No. 151 (February 28, 1968).
We are asked by the Board to enforce its remedial order; Saco-Lowell requests it be vacated. Our province is limited to the ascertainment of the substantiality of the evidence underlying the Board’s action. Universal Camera Corp. v. N.L.R.B., 340 U.S. 474, 71 S.Ct. 456, 95 L.Ed. 456 (1951). As we cannot say that the proof did not meet the requisite standard, we will enforce the decision of the Board.
Order enforced.

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