Firm 1 is pricing at marginal cost, the best response if the other guy is pricing at marginal cost is to price at marginal cost or above.

公司1定价在边际成本,针对对手定价在边际成本的最佳对策,是定价高于或等于边际成本

耶鲁公开课 - 博弈论课程节选

Now this is marginal cost or above so this is the best response.

现在就是高于或等于边际成本,所以这是最佳对策

耶鲁公开课 - 博弈论课程节选