问题如下：
Which is the primary advantage of the option-adjusted
spread (OAS) over the static spread?
选项：
A. OAS uses the entire term structure instead of a single
point
B. OAS, being a valuation model, is not biased by the
market price of the bond
C. OAS allows for cash flow changes due to interest rate
changes
D. None, they are the same
解释：
This is the key idea: while static (Z) spread treats
the term structure of rates as static, the OAS simulates several interest rate
paths and therefore can model cash flow changes. In regard to (A), this is not
correct because both OAS and static spread use the entire term structure. In
regard to (B), this is false: OAS solves for yield that equates to market
price.
