GKFix MCQ Question

What is the correct expression for Ka of HF based on equilibrium concentrations?

• A. Ka = [HF]/[H3O+][F–]
• B. Ka = [H3O+]^2
• C. Ka = [H3O+][F–]/[HF]
• D. Ka = [HF][H2O]/[H3O+][F–]