3. the direction of the centripetal force acting on a ball on a string being spun in a circle around a person is

a. outward-seeking.
b. parallel to the person.
c. perpendicular to the person.
d. center-seeking.

The correct answer is "center-seeking".

Explanation:

Centripetal force is the force which is required to keep the body in the circular motion. The direction of the centripetal force is towards center of the circle.

The expression for the centripetal force is as follows;

Here, r is the radius, v is the velocity and m is the mass of the object.

Without this force, the body cannot move in the circular motion. Then, it follows the straight line motion.

The direction of the centripetal force acting on a ball on a string being spun in a circle around a person is center-seeking.

Therefore, the correct option is (D).