In a return-standard deviation space, which of the following statements is(are) true for riskaverse investors? (The vertical and horizontal lines are referred to as the expected return-axis and the standard deviation-axis, respectively.) I) An investor's own indifference curves might intersect. II) Indifference curves have negative slopes. III) In a set of indifference curves, the highest offers the greatest utility. IV) Indifference curves of two investors might intersect. A) I and II only B) II and III only C) I and IV only D) III and IV only E) None of the options are correct