CMC Corporation announced a new product yesterday, and the stock price of CMC Corporation experienced a rate of return of 5%. The market index also increased by 5% yesterday. If the market is efficient, this implies that (A) the market treated CMC's announcement as good news. (B) the market treated CMC's announcement as bad news. (C) the market was neutral about CMC's announcement. (D) we cannot determine the market reaction to CMC's announcement unless the risk-free rate is given. (E) None of the above.