The Stock expected to earn 0.32 in book , 0.16 in normal economy and -0.18 in bust. Stock Y is expected to earn 0.17 in boom , 0.12 in normal economy and -0.08 in bust the probability of a boom is 5 percent , the probability of a normal economy is 92 percent and the probability of bust is 4 percent. What is standard deviation of returns per n a portfolio that is invested in stock x and stock y if the 30 percent of the portfolio is invested in stock x and 70 percent is invested in stock y ?

A ) 6.24 percent

B ) 8.46 percent

C)4.32 percent

D ) 7.18 percent

E ) 5.15 percent