[单选题]
According to the second law of thermodynamics, for o 4 xup*ty/r:nany process that 6e jpui4yxa47 may occur within an isau 7j6 ieyx4p4olated system, which one of the choices applies?
A. Entropy remains constant.
B. Entropy increases.
C. Entropy decreases.
D. Both A and B are possible.
E. Both A and C are possible.