The surface area of the rectangular prism would be C. 120 cm².
This is because there are two of each face (top and bottom, front and back and two sides). This means that when calculating the surface area, we just take the measures of these faces and double them.
2(20) + 2(16) + 2(24) = Surface Area
40 + 32 + 48 = Surface Area
120 cm² = surface area
