Alabor agreement stipulating that employers, although free to hire whomever they choose, may retain only union members and that all employees hired into positions covered under the terms of a collective bargaining agreement must, after a specified probationary period of typically thirty to sixty days, join the union or forfeit their jobs is known as a

Union shop

Explanation:

Union shop

it is referred to clause that allow employer to hire members who are already in the union or hire any individual who are not the member of the union for given period of time. it is legal in those state only that has not  enforced right to work law and not legal to that  state that allow practice of charging some amount from employee to the union.

answers

a: apartment building

b: bank

d: office.

hope it

the answer is b for dog