Explain the importance of credibility when evaluating a firm's potential moves. For example, if firm two is the "responder" in a Stackelberg game, it may threaten to flood the market if firm one (the "leader") does not set a low quantity (say, ½ of the monopoly quantity). Should firm one consider this threat to be credible? How might the answer change if firms are playing this "game" repeatedly over many periods? What are some strategies that firm two can use to gain credibility?