The Year 2 fiscal year-end financial statements for Walter Co. report revenues of $55,076 million, net operating profit after tax of $9,954 million, net operating assets of $58,017 million. The Year 1 fiscal year-end balance sheet reports net operating assets of $58,488 million. Walter's Year 2 net operating profit margin is: Select one: a. 11.6% b. 17.2% c. 17.0% d. There is not enough information to calculate the ratio. e. 18.1%