问题如下：
Expected loss may increase with a decrease in a bond's:
选项：
A.loss severity.
B.default risk.
C.recovery rate.
解释：
C is correct.
Expected loss = default risk x loss severity ( loss given default) = default risk x (1-recovery rate).
A decrease in the recovery rate will increase the expected loss.
那同样default risk上升，也会让expected loss上升啊。
