You live on the 20th floor of a building with two elevators, A and B, of the same mass. To go to floor 20, elevator A accelerates for the first 10 floors, then decelerates for the last 10. Meanwhile elevator B accelerates for 5 floors, moves at a constant speed for 10 floors, then decelerates for 5 floors. Both elevators complete the trip in the same amount of time. You are environmentally conscious, so you want to take the elevator which uses the least electricity. Assume friction in the motors and air drag are negligible. Which elevator should you take?
A. Elevator A.
B. Elevator B.
C. Both elevators use the same amount of electricity.
D. Can't say without more information.