Staley Co. manufactures computer monitors. The following is a summary of its basic cost and revenue data:

	Per Unit	Percent
Sales price	$480	100
Variable costs	312	65
Unit contribution margin	$168	35

Assume that Staley Co. is currently selling 600 computer monitors per month and monthly fixed costs are $80,000. Staley Co.'s margin of safety ratio (MOS%) if 600 units are sold would be (round intermediate calculation up to nearest whole number of units):

A.

33.4%.

B.

17.7%.

C.

20.5%.

D.

19.5%.

E.

79.5%.