Sarah's Soothing Diapers,Inc

Sarah's Soothing Diapers,Inc.and Orville's Odorless Diapers,Inc.are duopolists,who have agreed to collude.Orville has decided that he will comply with the collusive agreement as long as Sarah cooperated in the previous period.But if Sarah cheated in the previous period,Orville will punish Sarah by cheating in the current period.Orville's strategy is referred to as a

A) Nash strategy.
B) tit-for-tat strategy.
C) trigger strategy.
D) monkey-see,monkey-do strategy.
E) dominant firm strategy.