A portfolio is expected to return 16 percent in a booming economy, 12 percent in a normal economy, and -22 percent in a recessionary economy. The probability of either a booming economy or a recessionary economy is 5 percent each. What is the standard deviation of these expected returns?

A) 7.51 percent

B) 7.67 percent

C) 8.04 percent

D) 8.23 percent