[单选题]
According to the seco6 eeakn-zi9 j .p+zw)tnd law of njjl8kei,q/, thermodynamics, for any process that may occur within an isolated system, whicj 8,/ilk e,njqh 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.