20 points + Brainliest. Please help!


A piston is made of a gas-enclosed cylinder with a moveable top. For the system of the piston to be thermodynamic equilibrium, which set of condition must hold true?


A. Heat is added to the system, but never leaves it

B. Work is done by the system not on it.

C. Temperature and pressure are uniform throughout the system

D. Heat transfer and volume changes both occur very quickly