Which of the following is true? a. Competitive forces are stronger in markets with high entry barriers than in those where entry barriers are low. b. If the production of a good is highly profitable relative to other industries, new competitors will enter as long as there are not barriers preventing them from doing so. c. Firms generally have no incentive to spend resources seeking the enactment of government legal barriers that would protect them from competition. d. High barriers to entry are only the result of natural market factors such as economies of scale, never artificial factors like government regulations or laws