For each of the following pairs of investments, indicate which would always be preferred by a rational investor (assuming that these are the only investments available to the investor): a. Portfolio A Portfolio B r = 148 r = 100 0-16 0 - 160 Preference Portfolio Portfolio B O Indeterminate b. Portfolio C Portfolio D - 110 98 0 148 OBS Preference: Portfolio C O Portfolio D Indeterminate c. Portfolio E Portfolio P = 180 r = 188 0208 0 - 148 Preference: O Portfolio E O Portfolio F Indeterminate