Forey, Inc., competes against many other firms in a highly competitive industry. Over the last decade, several firms have entered this industry and, as a consequence, Forey is earning a return on investment that roughly equals the interest rate. Furthermore, the four-firm concentration ratio and the Herfindahl-Hirschman index are both quite small, but the Rothschild index is significantly greater than zero. Based on this information, which market structure best characterizes the industry in which Forey competes? Explain.