Pick out the correct statement:

A. In an isothermal system, irreversible work is more than reversible work

B. Under reversible conditions, the adiabatic work is less than isothermal work

C. Heat, work, enthalpy and entropy are all 'state functions'

D. Matter and energy cannot be exchanged with the surroundings in a closed system

Please do not use chat terms. Example: avoid using "grt" instead of "great".