Bennys Corporation manufactures 20,000 wrenches each year. The following costs include direct materials of $5/unit; direct labor of $20/unit; variable manufacturing overhead of $2.50/unit and fixed manufacturing overhead of $11.00. An outside supplier has offered to sell 20,000 wrenches to Benny for $30 per wrench. If all of Benny's fixed manufacturing overhead is unavoidable, the "make or buy" decision would be:

a) Buy from supplier because Benny has a total cost per unit to make lower than the supplier

B) Buy from supplier because Harrison has a total cost per unit to make higher than the supplier

C) Make in house because the total cost per unit is lower than the cost from the supplier

D) Make in house because the variable cost per unit is lower than the cost from the supplier