Which of the Following Statements Is False

Which of the following statements is false?

A) If indeed alphas are positive, it is possible that the positive alpha trading strategies contain risk that investors are unwilling to bear but the CAPM does not capture.
B) If indeed alphas are positive, it is possible that the costs of implementing investment strategies are larger than the NPVs of undertaking them.
C) If indeed alphas are positive, then investors have to be systematically ignoring positive-NPV investments opportunities.
D) The only way a positive NPV investment opportunity can exist in a market is if some barrier to entry restricts competition.