Answer:
A. The acceleration is the same for both bullets.
Step-by-step explanation:
The force of gravity is the attractive force applied by the earth on any object on its surface or neighborhood. And it is uniform under free fall at a definite location on the earth.
Since the the two bullets motion was at the same time and without air resistance, their acceleration would be the same before striking the surface of the water. This is because neglecting air resistance, all objects at the same height would fall with the same acceleration no matter their masses.