Sam purchased a 30-year, zero-coupon bond with a yield to maturity (YTM) of 5%. After holding it for 5 years, he sold it. (Note: Assume annual compounding.)

a. Assume the bond's YTM is 5% when he sells it, what is the IRR of his investment?

b. Assume the bond's YTM is 6% when he sells it, what is the IRR of his investment?

c. Even if a bond has no chance of default, is your investment risk free if you plan to sell it before it matures? Explain.