Answer:
B) Remains constant
Explanation:
The motion of the ball is the motion of a projectile, which consists of two separate motions:
- A horizontal motion with constant velocity, since there are no forces acting along the horizontal direction (if we neglect air resistance)
- A vertical motion with constant acceleration, due to the presence of the force of gravity (pointing downward), that accelerates the ball towards the ground with acceleration g=9.8 m/s^2.
We are only interested in the horizontal motion of the ball: we said that there are no forces acting along the horizontal direction, therefore the horizontal component of the the velocity of the ball is constant.