GKFix MCQ Question

What is the equilibrium constant expression for PCl₅ ⇌ PCl₃ + Cl₂?

• A. K = [PCl₅] / [PCl₃][Cl₂]
• B. K = [PCl₃] + [Cl₂] / [PCl₅]
• C. K = [PCl₃][Cl₂] / [PCl₅]
• D. K = 2[PCl₃][Cl₂] / [PCl₅]