GKFix MCQ Question

What is the formula for calculating average molar mass of a mixture?

• A. (M1 + M2 + ... ) / (n1 + n2 + ... )
• B. (M1n1 + M2n2 + ... ) / (n1 + n2 + ... )
• C. (M1 + M2 + ... ) × (n1 + n2 + ... )
• D. (M1n1 + M2n2 + ... ) × (n1 + n2 + ... )