Answer:
C. Limited the powers of labor unions
Explanation:
The Taft–Hartley Act or Labor Management Relations Act of 1947, is a federal law in United States that limits the powers of labor unions and its activities.
The Act was implemented on June 23, 1947, under the veto of President Harry S. Truman.
It came into effect after the major strike wave in United States during 1945-46.
The law successfully amended the 1935 National Labor Relations Act. It clearly prohibits union from engaging into "unfair labor practices" like political strikes, jurisdictional strikes, boycotts, monetary donations etc.
The restrictions were imposed to keep a check on proper exercise of powers by the labor unions and to maintain a liberal market flow in America.