Staley Co. manufactures computer monitors. The following is a summary of its basic cost and revenue data: Sales price Per Unit $480 Percent 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. What is Staley Co.'s margin of safety (MOS), in units, if 600 units are sold and all costs and revenues are as budgeted? (Round intermediate calculation up to nearest whole number of units.) Multiple Choice 214. 123. 141. 128. 242