2. Which of the following statement is NOT the second law of thermodynamics?
(A) the entropy of a closed system can never decrease;
(B) the entropy of the universe can never decrease;
(C) it is impossible to construct a refrigerator operating in a cycle whose sole effect is to transfer heat from a cooler object to a hotter one;
(D) the change in the internal energy of a system depends only on the net heat transferred to the system and the net work done by the system, independent of the particular processes involved.