The average annual return over the period 1886-2006 for stocks that comprise the S&P 500 is

8.5%,

and the standard deviation of returns is

18%.

Based on these numbers what is a 95% confidence interval for 2007 returns?

A.

17.5%,

34.5%

B.

27.5%,

44.5%

C.

13.75%,

22.25%

D.

12.5%,

29.5%