The investments fund sells class a shares with a front-end load of 6% and class b shares with 12b-1 fees of 0.75% annually as well as back-end load fees that start at 5% and fall by 1% for each full year the investor holds the portfolio (until the fifth year). assume that you have $1,000 to invest and the portfolio rate of return net of operating expenses is 11% annually. a-1. if you invest in each fund and sell after 4 years