Identify the correct definition of a reversible thermodynamic process.
a) A process carried out infinitesimally slowly so that the system remains in thermodynamic equilibrium at every stage.
b) A process that returns the system to its initial state while leaving the surroundings in a different state.
c) A process that can be exactly reversed with no net change in entropy of the system and surroundings.
d) A process that yields maximum work even though the entropy of the system increases.