Answer:
The correct answer is letter "A": affordable food creates an external benefit rather than an external cost in the case.
Explanation:
Externalities are costs third parties have to be responsible for even if they were not involved in causing the externality. There are positive externalities and negative externalities. Positive externalities are those that third parties benefit from. Negative externalities affect third parties.
Thus, importing less-expensive but chemically-dangerous food will create a positive externality to consumers purchasing those types of foods since less money is getting out of their pockets without them having to influence discounts.