I believe the answer to this question is C. The pillow distributes the decelerating force over a greater amount of time .
sudden stops are damaging, not the fall itself.
When falling on a mat it will take longer since a smaller force=longer falling time
when falling on a wooden floor it will take shorter since a larger force=smaller falling time
Hence, if the sudden fall is what causes impact and discomfort, and a smaller force equals longer falling time, and a larger force equals shorter falling time and smaller falling time equals less impact, then, C. must be the answer.