Final answer:
No force is required to keep the ball moving with the same velocity.
Step-by-step explanation:
To keep the ball moving with the same velocity on a frictionless horizontal table, no force is required. Option a) 0 N is the correct answer. This is because an object in motion will remain in motion at a constant velocity unless acted upon by an external force, according to Newton's First Law of Motion.
Learn more about Newton's First Law of Motion