22 Which one of the following portfolios cannot lie on the efficient frontier as described by Markowitz? Portfolio Expected Return Standard Deviation 9% 21% X 5% 7% Y 15% 36% Z 12% 15% a. Only portfolio W cannot lie on the efficient frontier. b. Only portfolio X cannot lie on the efficient frontier. C. Only portfolio Y cannot lie on the efficient frontier. d. Only portfolio Z cannot lie on the efficient frontier. e. Cannot tell from the information given