GKFix MCQ Question

What is the correct equilibrium constant expression for the reaction Ni(s) + 4CO(g) ⇌ Ni(CO)₄(g)?

• A. Kc = [Ni(CO)₄][Ni]/[CO]⁴
• B. Kc = [Ni][CO]⁴/[Ni(CO)₄]
• C. Kc = [Ni(CO)₄]/[CO]⁴
• D. Kc = [CO]⁴/[Ni(CO)₄]