13.A stock had returns of 11 percent, -18 percent, -21 percent, 20 percent, and 34 percent over the past five years. What is the standard deviation of these returns? A. 18.74 percent B. 20.21 percent C. 20.68 percent D. 24.01 percent E. 23.49 percent 14.A stock had returns of 16 percent, 4 percent, 8 percent, 14 percent, -9 percent, and -5 percent over the past six years. What is the geometric average return for this time period? A. 4.26 percent B. 4.67 percent C. 5.13 percent D. 5.39 percent E. 5.60 percent