Final answer:
The appropriate force experienced during deceleration when the body is forced forward out of the seat is known as inertial force, answer D) Inertial force.
Step-by-step explanation:
The appropriate force that occurs when an accelerative force acts on the body in a chest-to-back direction during deceleration is inertial force. This is because when deceleration occurs, the seat (or any point of reference that is decelerating along with the body) is moving in one direction, while the inertia of the body wants to keep moving in the opposite direction due to Newton's first law of motion. Hence, the body is forced forward, as if an inertial force were acting upon it.
In the context of noninertial (accelerated) frames, such as when a car rapidly decelerates, a passenger feels as if they are being pushed forward out of the seat. This is not a real force but a pseudo-force from the point of view of the noninertial frame of reference. The correct answer to the student's question is D) Inertial force.