I am having trouble solving this problem...

In mid-2012, Ralston Purina had AA-rated, 10-year bonds outstanding with a yield to maturity of 2.22%. a. What is the highest expected return these bonds could have? b. At the time, similar maturity Treasuries had a yield of 1.22%. Could these bonds actually have an expected return equal to your answer in part (a)? c. If you believe Ralston Purina's bonds have 1.1% chance of default per year, and that expected loss rate in the event of default is 58%, what is your estimate of the expected return for these bonds