Which statement is FALSE about the National Labor Relations Act (NLRA)?

a. Employers can commit ULPs (unfair labor practices) by using inflammatory "scare tactics" and coercive techniques against the employees to prevent unionization.

b. Secondary boycotts of companies doing business with a company that the union is striking are permissible so as to enhance the union's power against the typically more powerful employer.

c. Supervisors and managers are not covered by the NLRA.

d. Both the employer and the union have a legal duty to bargain in good faith on the terms and conditions of a contract.