Given a text T, and several options, according to the question posed in the text T to choose the most appropriate option from the options as the answer, please directly output the most appropriate option, do not need to output the explanation.

If a researcher conducting empirical tests of a trading strategy using time series of returns finds statistically significant abnormal returns, then the researcher has most likely found:
Option A:a market anomaly.
Option B:evidence of market inefficiency.
Option C:a strategy to produce future abnormal returns.

Answer: A