For Which of the Following Reactions Will the Entropy of a System

Multiple Choice

For which of the following reactions will the entropy of a system decrease?

A) 2 NH₃(g) → N₂(g) + 3 H₂(g)
B) 2 C(s) + O₂(g) → 2 CO(g)
C) CaCO₃(s) → CaO(s) + CO₂(g)
D) 2 NO₂(g) → N₂O₄(g)
E) NaOH(s) → Na⁺(aq) + OH^-(aq)