The Table Below Shows the Payoff (Profit) Matrix of Firm

The table below shows the payoff (profit) matrix of Firm A and Firm B indicating the profit outcome that corresponds to each firm's pricing strategy (where $500 and $200 are the pricing strategies of two firms) .Table 12.2

-Which of the following is true of an externality?

A) An externality enhances the efficiency of the market system.
B) An externality is not an economic problem because it is external to the market.
C) An externality is a cost borne by the people who are directly or indirectly involved in the production of a good or service.
D) An externality accrues to someone who had nothing to do with the production or consumption of a good or service.
E) An externality refers to some unexpected change in the equilibrium price or quantity of a product.