The Best Shape for an Automobile to Have Is One

Multiple Choice

The best shape for an automobile to have is one that is streamlined both in the front and in the back. The reason for this is

A) to avoid uneven air flows that might push the vehicle sideways.
B) to improve fuel efficiency when driving in reverse.
C) to use the viscosity of the air to help propel the automobile forward.
D) to ensure the air flow remains laminar all the way around the vehicle.