Choose the Most Correct Statement: Where a Place of Employment

Choose the most correct statement: Where a place of employment is a union shop,

A) the employer may hire only persons who are already members of the union.
B) the employer may hire only persons who are already members of the bargaining unit.
C) an employee's employment is conditional on maintaining his or her union membership.
D) secondary picketing is prohibited.
E) all employees will have been provided from a hiring hall.