4. Pat Co. manufactures pocket calculators. Pat Co. frequently subcontracts work to other manufacturers, depending on whether Pat Company's facilities are fully utilized. A key component is Part A76 which costs as follows: Another manufacturer has offered to sell the same part to Pat Co. for $8 each. Of the fixed factory overhead costs, $15,000 could be avoided if the component were purchased. Further, if the component is purchased, the released capacity could be rented to another company for $8,000 per year. How different will operating income be if Pat co. buys the part? a. $3,000 increase b. $80,000 decrease c. $4,000 decrease d. $3,000 decrease e. None of the above