Can someone help me in finding out the right answer from the given options. When it is illegal to need a union membership as the condition of employment for a firm, then the firm: (1) Needs all the employees to sign yellow dog contracts. (2) Can’t sign an agency shop agreement with the union. (3) Can need arbitration before workers can go out on the strike. (4) Has a supplier’s contract with federal government. (5) Is operating in the state with ‘Right-to-Work’ law.