In the figure below, a right rectangular prism is cut in half by a plane that is perpendicular to the pyramid’s base. Which two dimensional figure is formed?

Urgent? will give brainliest given that the blue triangle is a right triangle, which expression correctly gives the area of the red square? a) a2 + b2 b) a2 - b2 c) a2 - c2 d) c2 - a2