One Stone Is Dropped from the Side of a Bridge

Multiple Choice

One stone is dropped from the side of a bridge, and a second is dropped from the same place a short time later (while the first stone is still in the air) . What is true about the distance between the stones as a function of time after both have been dropped (and before either reaches the ground) ? Ignore air resistance.

A) increases, finally reaching a constant value
B) always increases
C) is constant
D) decreases, and then reaches a constant value
E) always decreases