Consider an economy with two types of firms, S and I. S firms always move together, but I firms move independently of each other. For both types of firms there is a 30% probability that the firm will have a 20% return and a 70% probability that the firm will have a - 30% return. What is the expected return for an individual firm? A. -9% B. 15% C. 5% D. - 15%