Which of the Following Is True for a System at Equilibrium

Multiple Choice

Which of the following is true for a system at equilibrium?

A) .S°_sys = S°_surr
B) .S°_sys = -S°_surr
C) .S°_sys = S°_surr = 0
D) .S°_univ > 0
E) None of the above is a sufficient condition.