The Main Reason the National Industrial Recovery Act of 1933

The main reason the National Industrial Recovery Act of 1933 was declared unconstitutional was that:

A) It de-stabilized economic activity.
B) Allowed businesses to draw up codes of fair competition.
C) Employers could not interfere with employees' right to unionize.
D) One of its codes was applied to an employer which went beyond Congress' authority to regulate interstate commerce.
E) Unions did not have enough money to fund strikes.