The volume of a pyramid is calculated using the equation:

For the first pyramid, l= 7 in, w = 3 in, and h = 8 in. So the volume would be:

For the second pyramid, l = 6 in, w = 3.5 in, and h = 9 in. So the volume would be:

Therefore, only II has a volume of 63 cubic inches. The answer is G.