Which word is correctly used in the sentence?

been a lovely time.

it's
its

The correct answer is:  [A]  " It's" .

(the choice with the apostrophe).

"   It's  been a lovely time."

Note:  The word, "it's", {note: with the apostrophe}; is a contraction for "it is" or "it has".  In this case, it stands for "it has".  When you need to use "it is" or "it has",  you either:  1) write out the "it is" or "it has" ; or, 2) write "it's" (that is, with the apostrophe). 

What do you mean by this?