If a 5 yr. AA- General Dynamics note is yielding a 35% tax bracket investor 7.56125% while a comparable maturity note from Philadelphia, Pennsylvania is yielding 4.8735%. If the inflation rate is 2.2765%, which bond would the investor prefer and why? If the marginal tax rate for the investor increases to 38.95%, which bond would the investor prefer? What is the critical tax rate? Please show all your work.