Question

Which sentence uses apostrophes correctly?
A:The décor of the mens room looked like it had not been changed since the 1970’s.
B:The décor of the men’s room looked like it had not been changed since the 1970s.
C:The décor of the mens’ room looked like it had not been changed since the 1970’s.

Answer 1

The correct sentence would be (C) The décor of the men's room looked like it had not been changed since the 1970's.

Just for your info, in British English, you do not put an apostrophe in dates, so it would be 1970s. In American English we do put the apostrophe.