单选题 A Treasury bond due in one-year has a yield of 8.5 percent. A Treasury bond due in 5 years has a yield of 9.3 percent. A bond issued by General Motors due in 5 years has a yield of 9.9 percent. A bond issued by Exxon due in one year has a yield of 9.4 percent. The default risk premiums on the bonds issued by Exxon and General Motors are: Exxon General Motors ①A. 0.1% 0.6% ②B. 0.1% 1.4% ③C. 0.9% 0.6%