A manager is trying to decide whether to purchase a certain part or to have it produced internally, Internal production could use either of two processes. One would entail a variable cost of $15 per unit and an annual fixed cost of $280,000 the other would entail a variable cost of $18 per unit and an annual fixed cost of $206,000. Three vendors are willing to provide the part. Vendor A has a price of $20 per unit for any annual quantity up to 25,000 units. Vendor B has a price of $23 per unit if demand is 1,000 units or less, but $19 per unit (for all units) if demand is greater. Vendor offers a price of $22 per unit for the first 1,000 units, and $20 per unit for additional units. a. If the manager anticipates an annual demand of 15,000 units, which alternative would be best from a cost standpoint? b. At what quantity would alternatives Internal production 1 and Internal production 2 yield the same profit