In the image, the question asks about the type of cross section formed when a rectangular prism is cut parallel to its base.

When a rectangular prism is cut parallel to its base, the cross section will be the same shape as the base. Since the base of a rectangular prism is a rectangle, the cross section formed will also be a rectangle.

Thus, the correct answer is rectangle.

Would you like further details or clarification on this concept?

Here are some related questions you might find interesting:

1. What happens to the cross section of a rectangular prism when it's cut perpendicular to its base?
2. How do cross sections differ for other 3D shapes like cylinders or pyramids?
3. What is the definition of a cross section in geometry?
4. How does the angle of a cut affect the cross section of a shape?
5. Can a rectangular prism have a triangular cross section, and under what circumstances?

Tip: Remember that when a prism is cut parallel to any of its faces, the cross section will always match the shape of that face!