Last Year,you Created an Immunized Portfolio with an Average Maturity

Last year,you created an immunized portfolio with an average maturity date of 14.5 years,a yield-to-maturity of 9.8 percent,and a duration of 9.6 years.According to the policy of dynamic immunization,you should now modify your portfolio in which one of the following ways?

A) modify the yield-to-maturity to 9.1 percent
B) modify the portfolio so the average maturity remains at 14.5 years
C) modify the portfolio so the average maturity becomes 13.5 years
D) modify the portfolio so the duration remains at 9.6 years
E) modify the portfolio so the duration becomes 8.6 years