Answer:
B. Dominant Strategy
Step-by-step explanation:
A dominant strategy is one in which the individual wants higher payoff regardless of its others choice. In this strategy the individual does not consider what other players strategy is. They are looking for maximizing their returns.
In the given scenario Joe is also considering dominant strategy as he is not concerned with what strategy Sam will follow. Joe wants to keep its price at $3 per gallon even if Sam cuts the price.