Which of the following statement is the correct criterion of applying w, equation? O a. We use the equation with Sharpe ratio when we invest on a risk-free asset and two risky assets O b. We use the equation with risk aversion when risk aversion A is given We use the equation with Sharpe ratio when the investor can only trade two risky assets O d. None of the above O c. Which of the following statement is the correct criterion of applying w, equation? O a. We use the equation with Sharpe ratio when we invest on a risk-free asset and two risky assets O b. We use the equation with risk aversion when risk aversion A is given We use the equation with Sharpe ratio when the investor can only trade two risky assets O d. None of the above O c