Semi-strong efficiency implications
C is correct. Under semi-strong efficiency, public information such as earnings announcements is rapidly incorporated into prices, so statement I is correct. Because public information is already reflected in prices, fundamental analysis cannot consistently generate excess returns, so statement II is correct. Private information is not assumed to be reflected in prices under semi-strong efficiency, so insider information can still provide an advantage, making statement III correct. Therefore, all three statements are consistent with semi-strong efficiency.
Why A is incorrect: more than one statement is correct.
Why B is incorrect: all three statements are correct, not just two.