For a non-empty set?A?and a null set??, which one of the following relations is always correct?
(A)????A (B){?}? ?(C)A??? (D)A??=?A

Dear Student, 
your question is unclear and appears to be incomplete. Recheck your question and please be little specific about the ? sign to which you are referring here so that we can provide you with some meaningful help. 
Also, this question belongs to higher grade.
Look forward to hearing from you again!
Regards!