Media Music stock is expected to earn 12 percent in a normal economy, 20 percent in a strong economy, 35 percent in a booming economy, and lose 20 percent in a recession. The probability of a recession is 17 percent while the probability of a normal economy is 48 percent, the probablity of a strong economy is 28 percent, and the probability of a booming economy is 7 percent. What is the standard deviation of returns on this stock?

A. 14.73%

B. 19.01%

C. 10.17%

D. 15.05%

E. 16.49%