The demand curve for gasoline slopes downward and the supply curve for gasoline slopes upward. The production of the 200th gallon of gasoline entails the following:

• a private cost of $3.03;
• a social cost of $3.23;
• a value to consumers of $3.39.

Suppose the dollar amount of the externality, per gallon of gasoline, is constant, regardless of how much gasoline is produced. Then the externality could be internalized if producers of gasoline were

Group of answer choices

required to pay a tax of $0.20 per gallon of gasoline sold.

required to pay a tax of $0.16 per gallon of gasoline sold.

provided a subsidy of $0.16 per gallon of gasoline sold.

provided a subsidy of $0.20 per gallon of gasoline sold.