Final answer:
The frictional force is the cause of centripetal acceleration when a coin is stationary relative to a rotating turntable, making D) Frictional Force the correct answer.
Step-by-step explanation:
The force that causes the centripetal acceleration when the coin is stationary relative to the turntable is the frictional force. According to Newton's second law of motion, any net force causing uniform circular motion is called a centripetal force. The direction of this force is always toward the center of curvature, which is also the direction of the centripetal acceleration. In the case of a coin on a turntable, it is the friction between the coin and the surface of the turntable that provides the necessary centripetal force to keep the coin moving in a circle and prevent it from slipping.
Therefore, the correct answer to the question is D) Frictional Force. In similar scenarios, such as a car navigating a curve, the friction between the road and the car's tires acts as the centripetal force holding the car in a curved path. Any deviation from a straight-line path requires centripetal force, and in most practical situations on Earth, friction is the force that provides this centripetal acceleration.