ppose that investor A holds a portfolio (portfolio A) consisting of three shares. The portfolio return is equal to 9% while its risk (st.dev) equals 15%. The market portfolio (consisting of n shares) at this time of reference rewards investors with 15% and its risk equals 10%. 1.1 Is this portfolio (portfolio A) an efficient one? Explain. [596] 1.2 Suppose that the risk free interest rate is 2%, what is the diversification benefit of another investor (investor B) who holds a perfectly diversified portfolio (portfolio B) which embeds the same level of risk with that of portfolio A (i.e. ,-0-15%)? Explain. [12.5%) 1.3 How this portfolio (portfolio B) can be constructed? Explain. [12.5%) 1.4 How does the existence of the risk free interest rate affect the optimum portfolio construction? Explain. [20%]