possible Fastec Automobile Company fabricates automobiles. Each vehicle includes one transfer case, which is currently made in-house. Details of the transfer case fabrication are as follows: Volume Variable cost per unit Fixed costs 900 units per month $8 per unit $16,000 per month A Korean factory has offered to supply Fastec with ready-made units for a price of $12 per transfer case. Assume that Fastec's fixed costs are unavoidable, but that Fastec could use the vacated production facilities to earn an additional $7,500 of profit per month. If Fastec decides to outsource, monthly operating income will: A. decrease by $16,000 B. increase by $7,500 C. increase by $3,900 D. decrease by $25,500