Explanation:

The correct answer is B (9.57%). The percentage change in the bond's price can be estimated using the modified duration, which is calculated as:

$\text{Modified Duration} = \frac{\text{Macaulay Duration}}{1 + \text{YTM}} = \frac{10.0}{1.045} = 9.5694$

For a 100 basis point decrease in yield, the percentage price change is:

$\% \Delta P = -\text{Modified Duration} \times \Delta YTM = -9.5694 \times (-1\%) = 9.5694\% \approx 9.57\%$

• Option A (9.43%) is incorrect because it uses the coupon rate instead of the yield to maturity to calculate the modified duration.
• Option C (10.00%) is incorrect because it directly uses the Macaulay duration without adjusting for the yield to maturity.