In an agency problem known as debt overhang, if the company has risky debt outstanding, equity holders will choose to invest only if: Select one: O a. the NPV of the project is negative. o b. the profitability index of the project exceeds a cutoff equal to the relative riskiness of the firm's debt times its debt-equity ratio. O c. the debt holders will lose all their money. o d. the NPV of the project exceeds a cutoff equal to the relative riskiness of the firm's debt times its debt-equity ratio