单选题 An analyst has noticed lately that the price of a particular bond has risen less when the yield falls by 0.5% than the price falls when rates increase by 0.5%. He could include that the bond:

A、 has negative convexity.
B、 is an option-free bond.
C、 has an embedded put option.

【正确答案】 A

【答案解析】[解析] 如果债券的凸度为负，则在收益率向不同方向变动相同比例的情况下，债券价格上升的金额将小于债券价格下降的金额。因此，本题的正确选项为A。