Arectangular pyramid is sliced such that the cross section is perpendicular to its base and the cross section does not intersect its vertex.

what is the shape of the cross section?

square

trapezoid

triangle

rectangle

The vertex, would be the tip of the pyramid. If it was sliced at the vertex, the shape would be a triangle. Since the slice doesn't intersect the vertex, the point of the pyramid would net be included, it would be as if the tip was cut off.

You would then have a trapezoid, because the top would be a straight horizontal line parallel with the bottom line.