Which of the Following Is an Accurate Definition of a Union

Which of the following is an accurate definition of a union shop?

A) A union security provision that requires a person to join the union within a certain amount of time after being hired
B) A union security provision that requires payment of dues but not a membership
C) A union security provision that requires a person to be a union member before being hired
D) A union contract provision that requires an employer to deduct union dues from employees' paychecks
E) A union contract provision that prohibits a person from joining the union within 30 days of employment