20. Which of the following statements about market efficiency is false?

a, If insider trading is prohibited (and the prohibition is enforced), the market will not be strong form efficient.

b. Even in an efficient market you will need to diversify.

c. It is a violation of weak form efficiency, if firms that manufacture luxury products systematically earn higher returns than firm that manufacture everyday staples.

d. It violates weak form efficiency if positive January returns systematically predict positive returns for the remaining 11 month of the year.