Problem 11-19 Diversification (LO3) Here are the returns on two stocks. Required: a-1. Calculate the variance and standard deviation of each stock. a-2. Which stock is riskier if held on its own? b. Now calculate the returns in each month of a portfolio that invests an equal amount each month in the two stocks. c. Is the variance more or less than halfway between the variance of the two individual stocks?Digital CheeseExecutive FruitJanuary+15+7February3+1March+5+4April+7+13May4+2June+3+5July23August82.