19. Which one of the statements below is false: A. The average beta across all stocks in a diversified index is l B. The beta of a firm is likely to change if the firm changes its industry. C. As long as a firm stays in the same industry, its beta will never change. D. An increase in the leverage of a firm will increase the firm's beta. E. Large firms, such as Air Canada and Bombardier, should not use their respective industry betas as an estimate for their own firms' betas