Elly Industries is a multi-product company that currently manufactures 30,000 units of Part MR24 each month for use in production. The facilities now being used to produce Part MR24 have a fixed monthly cost of $150,000 and a capacity to produce 35,000 units per month. If Elly were to buy part MR24 from an outside supplier, the facilities would be idle, but its fixed costs would continue at 40% of their present amount. The variable production costs of Part MR24 are $11 per unit.

If Elly industries is able to obtain Part MR24 from an outside supplier at a unit purchase price of $15, the monthly usage at which it will be indifferent between purchasing and making Part MR24 is:

a. 32,000 units

b. 22,500 units

c. 30,000 units

d. 35,000 units