(A) increases by 2
When each observation is increased by 2, the middle value also shifts up by 2, so the median increases by 2.
Median depends on the positional value of the middle observation. If every observation increases by a constant k, the entire data shifts by k, so the median also increases by k. Here k = 2, so the answer is (A). Options (B) and (D) are incorrect; (C) would be true only if the data were unchanged.