Suppose you purchase a 30-year zero-coupon bond with a yield to maturity of 5.9%. You hold the bond for five years before selling it . a. If the bond's yield to maturity is 5.9% when you sell it, what is the rate of return of your investment? b. If the bond's yield to maturity is 6.9% when you sell it, what is the rate of return of your investment? c. If the bond's yield to maturity is 4.9% when you sell it, what is the rate of return of your investment? d. Even if a bond has no chance of default, is your investment risk free if you plan to sell it before it matures? Explain