The volume of a pyramid is given by the formula:
V = (1/3) * B * h
where B is the area of the base and h is the height of the pyramid.
If pyramid A is a dilation with scale factor 4 of pyramid B, then the ratio of their corresponding side lengths is 4:1. Since volume is a cubic function of length, the ratio of their volumes is the cube of the scale factor:
V_A / V_B = (4/1)^3 = 64
Therefore, the volume of pyramid A is 64 times the volume of pyramid B.
The answer is (d) 64 times Va.