Answer:
The answer is: All the options are correct (I, II and III)
Explanation:
The larger the number of individuals (e.g. securities analysts, investors) who are informed about the price system of securities, the prices of securities will approach informational efficiency.
When the system approaches informational efficiency, you can determine which securities are riskier than others. Therefore you can price riskier securities so that they offer higher expected returns.
The other positive effect of informational efficacy is that investors can determine which securities are undervalued or overvalued.