Delco Accents stock is expected to earn 5 percent in a weak economy, 17 percent in a normal economy, 25 percent in a strong economy, 30 percent in a booming economy, and lose 25 percent in a recession. The probability of a recession is 7 percent, the probability of weak economy is 15 percent, the probability of a normal economy is 46 percent, the probablity of a strong economy is 25 percent, and the probability of a booming economy is 7 percent. What is the standard deviation of returns on this stock? A. 12.73% B. 15.05% C. 10.71% D. 16.94% E. 13.02%