Westover stock is expected to return 36 percent in a boom, 14 percent in a normal economy, and lose 75 percent in a recession. The probabilities of a boom, normal economy, and a recession are 2 percent, 93 percent, and 5 percent, respectively. What is the standard deviation of the returns on this stock?

19.90 percent

20.52 percent

20.41 percent

18.79 percent

19.74 percent