Question

Which sentence does not contain any errors?

A.
She couldnt remember which suitcase was yours.

B.
She couldn't remember which suitcase was yours.

C.
She couldn't remember which suitcase was your's.

D.
She could'nt remember which suitcase was yours'.

Answer 1

The answer is:
B.
She couldn't remember which suitcase was yours.
 
Couldn't has its apostrophe between the "n" and the "t", and yours is used properly. 

Answer 2

b because she couldn't rember what suitcase whast youras