Which of the following shapes could be formed by taking a longitudinal section perpendicular to the base of a rectangular prism?

1 A rectangle or a trapezoid

2 A rectangle or a triangle

3 A rectangle only

4 A trapezoid only

3. A rectangle only.

Step-by-step explanation:

The section is perpendicular to the base so it can only be a rectangle.

The section could cut through opposite sides of the prism or adjacent sides, but in each case the section will be rectangular.