A portfolio's expected return is 12%, the standard deviation of 22%, and the risk-free rate is 5%. Answer the following: (6 points) a. What is the portfolio's Sharpe ratio? b. Which of the following would make for the greatest increase in the portfolio's Sharpe ratio? (Show your calculations) i. An increase of 1% in expected return ii. A decrease of 1% in the risk-free rate iii. A decrease of 1% in its standard deviation