问题如下：
TXT is a derivatives trading company. The derivatives trading company sold $10 million five-year CDS protection on company D. The CDS contract has a duration of 3.5 years. 3 months later, the credit spread on company D narrowed from 225bps to 165 bps.
According to the information above, if TXT enters into an offsetting position, it will generate a profit closest to:
选项：
A.0.21 million
B.0.58 million
C.0.79 million
解释：
A is correct.
考点：计算CDS的盈利.
解析：
根据公式，TXT的盈利为：
Profit for TXT = changes in spread in bps × duration × notional
=（225bps-165bps）×3.5×10million
= 0.21 million
题目中的duration有带一个years，我知道是当做修正久期使用，但是怎么区分不是麦考利久期？
