A 0.20kg phone is dropped from rest from a height of 1.0m onto a hard floor. Without a protective case, the phone comes to rest after compressing 1.5mm at the point of impact. With a shock-absorbing case installed, the phone instead compresses 6.0mm before stopping. Assume the force exerted on the phone is constant during each compression. What is the ratio of the magnitude of the average force on the phone with the case to that without the case?
a) 4.0
b) 0.33
c) 0.25
d) 2.0