19. A portfolio holds stock A and stock B in equal amounts. Stock A has a 50% chance of earning 10% if the economy does well and a 50% chance of earning 2% if the economy performs poorly. Stock B has a 50% chance of earning 3% if the economy does well and a 50% chance of earning 5% if the economy does poorly. What is the portfolio's coefficient of variation? a. 0.30 b. 3.33 c. 5 d. 0.50