the empty set belongs to set A.true or false and how?

Empty/ Null set is a subset of every set.

The proof is as follows:

Let A be any set.
Now, to show the empty set phi is a subset of A, we have to show that:
All elements of phi are in A.

There is no element in phi which is not in A. If there was indeed any, then the null set would contain elements, which goes against its definition.

 

Hence, Empty/ Null set is a subset of every set.