The correct answer is C.
The National Labor Relations Act ( also known under the name of Wagner Act ) was signed into law by President Franklin Roosevelt on July 5, 1935.
It was a United States Labor Law which protected the rights of workers in the private sector. It addressed the relations between unions and employers in the private sector.
The employees were given the right to self-organization and to join or assist labor organizations. Collective actions such as strikes were also approved.
The Act banned various unlawful and unfair labor practices as well.