The resulting cross-section of a trapezoidal prism when sliced by a plane section vertically could be a trapezoid or a rectangle, depending on the angle of the plane section relative to the base of the prism. Therefore, the correct answer is either B or D depending on the specific angle of the plane section.
If a trapezoid prism is sliced by a plane section vertically, the resulting cross-section is a rectangle. Therefore, the answer is D.
