[单选题]
According to the second law of thermodynamics, fo +2a gvjk:v)sdfu*ii* r ana.9ie cccqd cp8m-d57y process that may occur within an isolated system, which dcci.ecqadmcp57 -9 8one 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.