In a System Composed of Gas Contained in a Cylinder

Multiple Choice

In a system composed of gas contained in a cylinder fitted with a piston,an adiabatic expansion causes the temperature of the gas to drop because

A) heat is given up by the system when the piston moves.
B) the pressure of the gas remains constant.
C) work is done on the system as the gas expands.
D) work done by the system is entirely at the expense of its internal energy.
E) heat is absorbed by the piston when it does work.