Which of the Following Is an Example of a Union

Which of the following is an example of a union unfair labor practice?

A) Sam,a union member,is threatened by Rashida,his boss,with loss of benefits if he votes for a union.
B) Graciela,an operations head,threatens to close down a plant if organized by a union.
C) Lillian,a new employee,refuses to join a union.
D) Hill,a nonunion employee,spies on union meetings.
E) Nestor,a union representative,makes a contract that requires his employer to hire employees satisfactory to the union.