Answer:
The answer is rectangle.
Step-by-step explanation:
A rectangular pyramid is sliced so the cross section is parallel to its base.
The shape of the cross section is a rectangle.
Given is that the figure is a rectangular pyramid. this means the base is rectangle. So, if something is cross sectioned parallel to a rectangle, it will also be a rectangle. The base is a rectangle, so a cross section parallel to the base is also a rectangle.
