Answer:
B. (5, 2)
Step-by-step explanation:
The coordinates of a midpoint of a segment that goes from (x1, y1) yo (x2, y2) are

So, the midpoint of HJ can be founded replacing (x1, y1) by H(3, 5) and (x2, y2) by J(7, -1)

Therefore, the answer is
B. (5, 2)