Costco Wholesale's stock has a 50% chance of producing a 25% return during 'boom times, a 30% chance of producing a 10% return during an average economy, and a 20% chance of producing a -29.25% return during a recession. What is the firm's expected rate of return? a. 9.41% b.9.65% C. 9.90% d. 10.15% e. 10,40%