The last four years of returns for a stock are as follows: Year 1 2 3 4 Return negative 3.8% 28.4% 11.6% 3.8% a. What is the average annual return? b. What is the variance of the stock's returns? c. What is the standard deviation of the stock's returns? a. What is the average annual return? The average return is nothing%. (Round to two decimal places.)