Six years ago, you purchased 450 shares of common stock for $34.25 per share. Since that time, the annual returns were 4.3%, (2.9%), 7.8%, (1.1%), 8.9%, and 3.8%. Based on these annual returns, calculate the stock's standard deviation and the range of returns within which you'd expect the annual return to be within 95% of the time. Select one: a. (8.37%) to 15.93% b. (14.66%) to 20.33% c. (12.84%) to 17.81% d. (15.25%) to 21.08% e. (5.94%) to 12.87%