Answers:
The players '
Policemen s's
Girlfriend's
Step-by-step explanation:
We can show that one thing is connected to or belongs to something by introducing a possessive apostrophe at the end of the subject that is functioning as owner of the object, usually followed by the letter "s". This is the case of policemen's and girlfriend's.
The players' is an exception to the rule because, since players is a plural noun that ends in an "s", there is no need to add another "s" after the apostrophe.