Parts Company has affered to sell 10,000 units of Part B89 to whiteside Corporation for $20.40 per unit. What should Whiteside Corporation do? A. Make the part and save $12.80 per unit. B. Buy trom Nadal Parts Company and lose $1.20 per unit. C. Make the part and save $4.50 per unit. D. Make the part ard siave $9.70 per unit