A cement manufacturer has supplied the following data.

Ton of cement produced and sold $225,000

Sales Revenue $929,000

Variable manufacturing expense $298,00

Fixed manufacturing expense $263,000

Variable selling and administrative expense $166,500

Fixed selling and administrative expense $83,000

Net operating income $98.500

The companys contribution margin ratio is closest to: a.) 37% b.) 50.0% c.) 69.5% d.) 10.6%