What Was a Major Change Brought About by the National

What was a major change brought about by the National Labor Relations Act of 1935?

A) It established the national minimum wage.
B) It broke up business monopolies in order to give workers more choice in employer.
C) Workers were given the right to bargain collectively.
D) It eliminated the ability of companies to bargain directly with unions.
E) It reduced the ability of workers to go on strike indefinitely.