Staley Co Manufactures Computer Monitors

Staley Co. manufactures computer monitors. The following is a summary of its basic cost and revenue data:Assume that Staley Co. is currently selling 600 computer monitors per month and monthly fixed costs are $80,000.
What is Staley Co.'s degree of operating leverage (DOL) at this sales volume (i.e., at 600 units) ? (Round your answer to three decimal places.)

A) 5.118.
B) 4.405.
C) 5.630.
D) 5.000.
E) 4.846.