Without the excel file what is the thought process to solve this

B C D E F G H I Q\#8. [15 Points] Apply Bond Immunization strategy given the following conditions: The par value is $1000, Maturity is 20 years, Coupon rate is 8%, and YTM (now) is 8% (Case I). Use the same format as the second tab (BOND PORTFOLIO IMMUNIZATION) of the attached excel file that has examples on immunization and find all the components in that spreadsheet and most importantly assess at what time (year) a change in YTM to 7\% (Case II) and YTM to 9\% (Case III) will result in the same bond value as the case when YTM is 8%. Note: include only the screenshot of your excel file together with your interpretation (narration) of your result and don't upload the whole excel file