Diagram shows two balls released from a device at the same time. the ball on the left falls freely from rest, and the ball on the right is launched horizontally which best compares the vertical motion of the two balls?

a)both balls have constant velocity and are acted on by gravity.
b)both balls are acted on by gravity and are accelerating downward.
c)both balls are pulled downward and have zero acceleration.
d)both balls have zero acceleration and have constant velocity.