A cement manufacturer has supplied the following data:

Tons of cement produced and sold		245,000
Sales revenue	$	949,000
Variable manufacturing expense	$	226,000
Fixed manufacturing expense	$	295,000
Variable selling and administrative expense	$	153,600
Fixed selling and administrative expense	$	87,000
Net operating income	$	187,400

The company's contribution margin ratio is closest to:

a. 45.1%

b. 60.0%

c. 68.9%

d. 19.7%