Six years ago, you purchased 100 common shares of a company for $34.91 per share. The stock pays an annual cash dividend of $1.35. The annual returns on the stock was 12%, 3%, (8%), 15%, 1%, and 13%. Calculate the standard deviation for your stock investment Select one: O a. 8.90% O b. 8.66% O c. 11.91% O d. 7.91% O e. 12.32%