Why Do Skates and Rays Have Flattened Bodies, While Sharks

Why do skates and rays have flattened bodies, while sharks are torpedo shaped?

A) Sharks have a strong cartilaginous skeleton that helps them maintain a tubular shape, whereas skates and rays lack such a skeleton.
B) Sharks are more closely related to the tubelike lampreys than skates and rays are.
C) Skates and rays need enlarged pectoral fins to help them stay level in turbulent water, whereas sharks do not.
D) Skates and rays exchange gases across their skin and thus require a high surface-area-to-volume ratio; sharks use gills to respire.
E) Sharks are streamlined for active swimming off the bottom; skates move about mostly on the ocean bed.