true or false if false why

19. The portfolio diversification effect requires that at least some assets are negatively correlated. 20. It is possible for the risk/return profile of individual assets to lie outside (i.e. left of) the efficient frontier.

21. Risk averse investors tend to have lower marginal utility when their consumptions are low.

22. A risk averse individual that has to decide between two different lotteries will always prefer a lottery with less risk.

23. Fama and French, in their 1992 study, found that firm size had better explanatory power than beta in describing portfolio returns.

24. The option price, follows a martingale under the risk-neutral measure Q when interest rate is zero.