I would have to disagree and say A

If there are 5 numbers then..

(A) If the median is 0..then the set could be

-10 -5 0 5 10

or

-20 -10 0 10 20

Either way they all add to 0

This is suff

(B) With this information alone, then this basically means the set of any 5 consecutive integers. This is not suff

From here we know that the answer is A

Now to combine them (this step is not necc once we know it is A, but anyways...)- If the range is 4, then that just means the specific set:

-2 -1 0 1 2.

This is just one specific example of something that (A) already tells you. GMAT does this a lot so that you think you need the info in (B), when it is actually just reconfirming something you already know from (A).

go with (A)