Rank the following bonds in order from lowest credit risk to highest risk, all with the same time to maturity, by their yield to maturity: (Rank: 1= lowest, 4 = highest)
a) Treasury bond with yield of 5.20 percent
b) United Airline bond with yield of 6.30 percent
c) Bank of America bond with yield of 9.12 percent
d) Hewlett-Packard bond with yield of 6.83 percent