Consider three assets, stock in Comp. A Airlines and stock in Comp. B Bus Company and stock in Comp. A shipping company. Suppose that Comp. A stock has a return of 11% two thirds of time and 9 % one thirds of time, Comp B stock has a return 15 % half of the time and 7% the other half of the time, and Comp C stock has a return 10% one thirds of time and 12% two thirds of time. What is the standard deviation of the returns on three stocks? Of these three stocks, which is riskier