The average annual return over the period 1926-2009 for the S&P 500 is 11%, and the standard deviation of returns is 20.6%. Based on these numbers, what is a 95% confidence interval for 2010 returns? O A. - 1.5%, 20.9% OB. - 10.6%, 31.3% O c. 30.2%, 73.1% OD. 30.2%, 52.2%