A firm has current assets that could be sold for their book value of $10 million. The book value of its fixed assets is $60 million, but they could be sold for $95 million today. The firm has total debt at a book value of $40 million, but interest rate changes have increased the value of the debt to a current market value of $50 million. This firm's market-to-book ratio is __________.

a. 1.83

b. 1.50

c. 1.35

d. 1.46