You discover that you can make above normal returns if you buy oil-company stocks just before noon on any given trading day, and sell them immediately before the market closes that same day. Which of the following describes this event
a. This would be a violation of weak form efficiency
b. This would be a violation of all forms of makret efficiency
c. This would be a violation of strong form of market efficiency
d. This could not be a violation of market efficiency
e. This would be a violation of semi-strong form efficiency