I need solution for this question: IF$,$ IFERROR, IFS, CHOOSE, and SWITCH functions. The file named Nancybonds.xlsx gives the bond rating for several bonds in a previous and future month. You want to efficiently count how many bonds were downgraded. Unfortunately, each company is listed in more than one row. Assuming you have sorted the data on the company name, how would you determine the number of downgraded bonds?