A cement manufacturer has supplied the following data: Tons of cement produced and sold 275,000 Sales revenue$979,000 Variable manufacturing expense$232,000 Fixed manufacturing expense$313,000 Variable selling and administrative expense$110,650 Fixed selling and administrative expense$93,000 Net operating income$230,350 The company's contribution margin ratio is closest to: Multiple Choice 44.3% 65.0% 68.0% 23.5%