11. The internal rate of return is best defined as; A) the discount rate that makes NPV rero. B) the difference between market value and cost D) profit as a perce that makes the NPV as large as possible E) the required rate of of investment 12. Bonds issued by the U.S. government A) are considered to be free of interest rate risk. B) generally have higher coupon rates than bonds issued by a corporation. C) are considered to be free of default risk. D) pay interest that is exempt from federal income taxes. E) are called "munis