A non-callable bond with 18 years remainin
题型：单项选择题
问题：
A non-callable bond with 18 years remaining maturity has an annual coupon of 7 percent and a $1000 par value. The current yield to maturity on the bond is 8 percent. Which of the following is closest to the effective duration of the bond（）
A. 9.63.
B. 11.89.
C. 8.24.