Is the US stock market efficient?

A. No. The market is never efficient and it is easy to earn an abnormal return.

B. No. No information of any kind is priced into stock prices.

C. Yes. The market is always efficient and all information is always priced in to stock prices.l

D. The US stock market is very efficient. It seems to be very difficult and expensive to legally earn a consistent abnormal return over time.

E. Yes. You cannot earn an abnormal return using any kind of public or private information.