Highfield Corporation has assets of $2,500, sales of $2,960, operating costs of $2,475, and $500 of total current liabilities consisting of $300 of accruals and $200 of notes payable. Its long-term debt is $1,150, its common equity is $850, its interest charges are $92, and its tax rate is 40%. What is Highfield's profit margin? a. 7.39% b. 7.58% c. 7.77% d. 7.97% e. 8.17%