A portfolio is invested 20 percent 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?

StateofProbabilityofRateofReturnifStateOccurs

EconomyStateofEconomyStockAStockBStockC

Boom.15.18.13.15

Normal.75.13.09.12

Recession.10-.25.02-.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

What is the answer and how to do solve for it?