When is the net force on an object equal to zero? A. When the object is in motion B. When the object is changing direction C. When the forces acting on the object are balanced D. When inertia is not present pls i need the answers quick

Two horses begin at rest. after a few seconds, horse a is traveling with a velocity of 10 m/s west, while horse b is traveling with a velocity of 13 m/s west. which horse had a greater acceleration? a. horse a because its change in velocity was greater than horse b's in the same time. b. horse b because its change in velocity was greater than horse a's in the same time. c. horse b because its change in velocity was the same as horse a's, but it took less time. d. both horses had the same acceleration.