The average annual return over the period 19262021 for the S\&P 500 is 12.6%, and the standard deviation of returns is 21.3%. Based on these numbers, what is a 67% confidence interval for 2022 returns? A. 1.3%,20.3% B. 8.7%,33.9% C. 26.1%,47.5% D. 26.1%,54.2%