b) DJS Investment Services must develop an investment portfolio for a new client. As an initial investment strategy, the new client would like to restrict the portfolio to the following three stocks: Stock Price/Share ($/share) Estimated Annual Return (%) AGA Products $50 6% Key Oil $100 10% XC Utility $80 8% The client has $50,000 to invest. DJS needs to ensure that the investment in Key Oil, the risker investment, has to be no more than 60% of the total investment. DJS can only purchase up to 800 shares of AGA Products, up to 400 shares of Key Oil, and up to 300 shares of XC Utility. The client has a requirement that the final portfolio can only include up to two stocks from the above list of stocks. Moreover, the stock AGA Products can be included in the portfolio only if the stock XC Utility is included. DJS seeks a portfolio that has maximum return. Formulate the binary programming model for the DIS Investment Services. Define the decision variables, objective function, and constraints. DO NOT SOLVE. (15 points) Hint: Let x1 = number of shares of AGA products purchased x2 = number of shares of Key Oil purchased x3 = number of shares of XC Utility purchased