[Solved] Which of the following is TRUE regarding the long run for a firm in monopolistic competition? A) The firm's economic profit equals zero. B) There are barriers to entry. C) Price exceeds average total cost. D) Marginal revenue is less than marginal cost. Colonoscope: A thin, flexible tube equipped with a camera and light at the end, used to examine the inside of the colon. Proctoscope: A medical instrument designed for the visual examination of the rectum. Valsalva Maneuver: A technique where one attempts to exhale forcefully with a closed mouth and pinched nose, used in medical examinations. Occult Blood: Blood present in such small quantities that it is not visible to the naked eye, often detected through specific tests.