Consider the Modigliani and Miller world of corporate taxes. An unlevered (all-equity) firm value is $400 million. By adding debt, the annual interest expense is $150 million, the corporate tax rate is 20%, and the discount rate on the tax shield is 8%. What is the value of the firm after adding debt? Select one: O a. $400 million O b. $875 million O c. $775 million O d. $1,000 million