A portfolio manager in charge of a bank portfolio has $10 million to invest. The securities available for purchase, as well as their respective quality ratings, maturities, and yields, are shown in the following table: Bond Quality scales Years to Yield to After-tasx Bond Bank's maturity maturity (%) yield (%) type Moody's name 4.3 5.4 5.0 4.3 2.7 2.5 A Municipal Aa C Government Aaa D Government Aaa E Municipal a5 Aa 15 Agency 2 4.54.5 The bank places the following policy limitations on the portfolio manager's actions: 1. Government and agency bonds must total at least $4 million. 2. The average quality of the portfolio cannot exceed 1.4 on the bank's quality scale. (Note that a low number on this scale means a high-quality bond). 3. The average years to maturity of the portfolio must not exceed 5 years. Assuming that the objective of the portfolio manager is to maximize after-tax earnings and that the tax rate is 50 percent, what bonds should be purchased? If it became possible to borrow up to $1 million at 2.75 percent after taxes, how should the formulation be changed