Answer: Fish A because of its elongated body and powerful tail.
Step-by-step explanation: An elongated body gives the fish a streamlined or fusiform shape. This enables them to slide more esily through water, thus decreasing the energy expenditure of the fish for swimming. Powerfull tails also enables them to swim over long distances as well as bursts of speed. This speed capability is vital when the fish will either try to avoid a predator or, if it is a predator itself, catch its prey.