不会没思路

问题如下：

The default correlation under a single-factor credit model is 4.9%. Both credits have the same individual default probabilities of 2%. The joint default probability is characterizes by a bivariate standard normal distribution. Below listed the asset correlations implied by various joint default probabilities. What is the implied asset correlation?

选项：

A.

0.1

B.

0.15

C.

0.2

D.

0.25

解释：