A run occurs when two consecutive changes are the same (i.e., two or more consecutive positive or negative price changes constitute one run). Tests found that the actual number of runs for a stock price series consistently fell into the range expected for a random series. The tendency for runs to persist was so slight that any attempt to exploit them would generate trading costs in excess of the expected abnormal returns. This indicates that the ______ effect is not a pricing anomaly.

A. value
B. event
C. overreaction