What bone assists in pulling the hand inward?

The correct answer is associated with the action of pulling the hand inward, which relates to the function of the muscles associated with the flexor group. Flexor muscles are responsible for the bending motion at the joints and are crucial in drawing body parts closer to the center of the body, including movements that involve the inward pulling of the hand.

In contrast, muscles or categories labeled as adductor typically refer to those that move limbs toward the body's midline rather than specifically describing hand movements. Extensor muscles are involved in straightening joints and extending limbs away from the body, which does not assist in the motion described. The radius, while a key bone in the forearm, plays a role in forearm motion and wrist movement but does not directly contribute to the action of pulling the hand inward. Thus, the flexor is the most appropriate answer in the context of inward hand movement.