A ball rolls down from the top of a grassy hill, reaches the bottom of the hill, continues to roll, and then starts to slow down and comes to a stop. What forces caused this ball's motion?
A.
Frictional force caused the ball to roll down the hill, but magnetism caused the ball to slow down and stop.
B.
Magnetic force caused the ball to roll down the hill, but air resistance caused the ball to slow down and stop.
C.
The force of the hill caused the ball to roll down the hill, but gravity caused the ball to slow down and stop.
D.
Gravity caused the ball to roll down the hill, but frictional force caused the ball to slow down and stop.