Suppose you buy equity of Apple and Pfizer with the following rates of return

Year

Rate of Return of Apple

Rate of Return of Pfizer

1	20%		10%
2	-10%		-4%
3	8%		30%

If the probability of each year is 1/3, the standard deviation of an equally weighted portfolio of Apple and Pfizer is:

A. 11.42%

B. 9.98%

C. 9.91%

D. 13.33%