问题如下：
Which of the followings is least likely the disadvantage of duration?
选项：
A.Duration applies to big changes in yield.
B.Duration provides a linear estimate of the percentage price changes.
C.The true relationship between the bond price and the yield-to-maturity is nonlinear.
D.Duration applies to only small changes in yield.
解释：
A is correct.
考点：Interest Rate Risk
解析：这道题目考察的是久期的缺点。BCD均是久期的缺点。A说当收益率变动比较大的时候，久期也是适合的。这是不正确的。久期的缺点是，只适合收益率变动比较小的情况。
对于答案解析有疑问，收益率变动较大的时候久期是不准的，不能用久期去衡量，应该说A选项谈不上Disadvantage因为本身说法就是错的。
