Given a text T, and several options, according to the question posed in the text T to choose the most appropriate option from the options as the answer, please directly output the most appropriate option, do not need to output the explanation.

The “second-order” effect on a bond’s percentage price change given a change in yield-to-maturity can be best described as:
Option A:duration.
Option B:convexity.
Option C:yield volatility.

Answer: B