The product W has per unit contribution of 8 with sold quantity of 124 units, the product X has per unit contribution of 5 with the sold quantity of 105 units, product Y has per unit contribution of 9 with sold quantity of 135 units, product Z has per unit contribution of 12 with sold quantity of 140 units then the weighted average mean is

• A. $11.75
• B. $10.75
• C. $9.75
• D. $8.75