Why Do Skates and Rays Have Flattened Bodies,while Sharks Are

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,while 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,while sharks do not.
D) Skates and rays exchange gases across their skin and thus require a high surface-area-to-volume ratio,while sharks use gills to respire.
E) Sharks are streamlined for active hunting,while skates and rays wait on the ocean bed to ambush prey.