A portfolio is invested 20percent in stock A, 50 percent in stock B, and 30 percent in stock C. Assuming the returns are normally distributed, what is the 68percent probability range of returns for any given year?

( Boom )State of Economy = 0.15 Stock A = 0.18 Stock B = 0.13 Stock C = 0.15

( Normal )State of Economy = 0.75 Stock A = 0.13 Stock B = 0.09 Stock C = 0.12

( Recession ) State of Economy = 0.10 Stock A = -.25 Stock B = .02 Stock C = -.20

a. -3.89 percent to 15.77 percent

b. -3.89 percent to 22.32 percent

c. 2.66 percent to 15.77 percent

d. 2.66 percent to 22.32 percent

e. 6.55 percent to 15.77 percent

Is the answer a, b, c, d or e? How do you solve for the answer?