Lincoln Company produces a part that is used in the manufacture of one of its products. The unit manufacturing costs of this part, assuming a production level of 5,000 units, are as follows: Erickson Company has offered to sell 5,000 units of the same part to Lincoln Company for $13 per unit. Assuming the company has no other use for its facilities and that the fixed manufacturing costs are unavoidable, what should Lincoln Company do? Make the part and save $1 per unit. Buy from Erickson and save $3 per unit. Make the part and save $3 per unit. Buy from Erickson and save $1 per unit