A backpack full of books and an empty backpack are dropped from the same height. If there is no air resistance, which bag will hit the ground first?

a
The full bag will hit the ground first.
b
They will both hit the ground at the same time.
c
The empty bag will hit the ground first.
d
This cannot be determined because the dimensions of the bags are needed.

b - They will both hit the ground at the same time.