Question 4 (15 points). The table below shows future one-year returns on two stocks A and B in three possible economic states. State (5) pts! A B Boom 0.20 50% 5% Normal 0.50 l 2% 5% Recess ion 0.30 -20% [5% (a) Calculate covariance and correlation between the two stocks (5 points}. (b) Please construct an opportunity set if an investor only holds the two stocks (10 points). (hint: you may calculate expected returns and standard deviations of portfolios under different portfolio weights of X and Y, draw the combinations of risk and return on a scatter plot. and connect the points to form the opportunity set curve)