Answer:
B. The horizontal cross-sections of the prisms at the same height have the same area.
Explanation:
Notice that the cone and the pyramid have the same volume. This is important.
This follows the Cavalieri's principle that, for the case of 3 dimensions, as the present case, it states, roughly, that if we have two bodies like the cone and the pyramid, and if we have parallel planes crossing each section, and we always have the same area, these two bodies have the same volume.
In this case, both, cone and pyramid have the same volume, then (reciprocally):
B. The horizontal cross-sections of the prisms at the same height have the same area.