The retums on the common stock of Wingstop Inc. are quite cyclical. The stock is expected to return 32 percent in a boom economy, 14 percent in a normal economy, and a negative 28 percent in a recessionary period. The probability of a recession is 25 percent while the probability of a boom is 20 percent. What is the standard deviation of the returns on this stock? Select one: O a. 32.08 percent O b. 21.41 percent O c. 39.77 percent d. 25.83 percent O e. 21.56 percent