Hitchcock Industries has developed two new products but has only enough plant capacity to introduce one of these products this year. The company controller has gathered the following data to assist management in deciding which product should be selected for production.

Hitchcock's fixed overhead includes proportional rent and utilities, machinery depreciation, and supervisory salaries. Selling and administrative expenses are not allocated to products.

Cost per unit:                                      Power Drill     Power Saw

Raw materials                                         $ 22.00          $ 18.00

Machining at $12/hr.                                      9.00             7.50

Assembly at $10/hr.                                     15.00             5.00

Variable O/H at $8/hr.                                   18.00             9.00

Fixed O/H at $4/hr.                                       9.00             4.50

Total unit cost:                                         $73.00           $44.00

Suggested selling price                                $ 88.98          $ 49.95

Actual research and development costs              $180,000          $95,000

Proposed advertising and promotion costs           $300,000         $250,000

The difference between the $49.95 selling price of Hitchcock's power saw and its total unit cost of $44.00 represents the unit

A. Contribution margin ratio.

B. Gross profit margin ratio.

C. Contribution margin.

D. Gross profit.