To avoid whiplash, the center of the headrest must be your ears.

The correct answer will be Option-A

Explanation:

Whiplash refers to the injury of the neck caused by the forward and backward movement of the neck. The person suffering from the whiplash feels the stiffness and neck pain causing trouble in neck movement.

The main cause of the whiplash is the rear-end accident of the auto accident which could be prevented by many of the ways in which one of the ways is by keeping the headrest of the vehicle above the ears.

Thus, option-A is the correct answer.

the gravitational force on an object increase as the mass of an object also, im not going to report you, but this question should be under the science category, not health