Please include the formulas and steps used, Thanks!

Mighty Safe Fire Alarm is currently buying 55,000 motherboards from MotherBoard, Inc., at a price of $64 per board. Mighty Safe is considering making its own boards. The costs to make the board are as follows: direct materials, $32 per unit; direct labor, $10 per unit; and variable factory overhead, $16 per unit. Fixed costs for the plant would increase by $85,000. Which option should be selected and why? a. make, $244,750 increase in profits X b. make, $330,000 increase in profits c. buy, $85,000 increase in profits d. buy, S244,750 increase in profits