A stock will have a loss of 14.6 percent in a recession, a return of 13.3 percent in a normal economy, and a return of 28 percent in a boom. There is 23 percent probability of a recession, 26 percent probability of normal economy, and 51 percent probability of boom. What is the standard deviation of the stock's returns?

a)15.56%

b) 28.81%

c) 12.73%

d) 16.97%

e) 14.55%