问题如下：
Compared with the
weighted average coupon rate of its underlying pool of mortgages, the pass-through rate on a mortgage
pass-through security is:
选项：
A. lower.
B. the same.
C. higher.
解释：
A is correct.
The coupon rate of a mortgage pass-through security is called the pass-through rate, whereas the mortgage rate
on the underlying pool of mortgages is calculated as a weighted average coupon
rate (WAC). The pass-through rate is lower than the WAC by an
amount equal to the servicing fee and other administrative fees.
同学您看看上述的公式哈，