A cloth manufacturing firm is deciding whether or not to invest in new machinery. The machinery costs $45,000 and is expected to increase cash flows in the first year by $25,000 and in the second year by $30,000. The firm’s current fixed costs are $9,000 and current marginal cost are $15. The firm currently charges $18 per unit. The current break-even quantity is
a. ​3000
b. ​600
c. ​500
d. ​300