The internal energy change when a system goes from state A and B is $40\; k\; J/mol$. If the system goes from A to B by a reversible path and returns to state A by an irreversible path, what would be the net change in internal energy ?

Question

( A ) zero
( B ) $<40 kJ$ <br/> ( C ) $40 kJ$
( D ) $> 40 kJ$