Please help. urgent. thank you.

A company produces three products, and currently has a shortage of machine hours since one of its two machines is down; only 420 hours are avallable this month. The selling prices, costs, and labor requirements of the three products are as follows: Required: a. What is the contribution margin per unit for each product? b. What is the contribution margin per machine hour for each product? c. Assume there is unlimited demand for each product. Which product should the company focus on producing