Newton approximated motion in a circle as a series of linear motions, as in the polygon below.

The answer is the option 3. (the arrow aimed to the center of the polygon)

Why?. Because the particle changed the direction of its movement due to a force inclined respect the motion and aimed to the center. Take in account that the vectors net force and acceleration are parallel.

3 X 1/2

Step-by-step explanation:

I started by eliminating C and B because of adding and subtraction in the problem.