Question: If there is a negative externality associated with the production of a private good, which of the following is an action by government that would most likely move the market to an efficient outcome?
A: Close the firm producing the good.
B: Subsidize the firm or its customers.
C: Tax the firm.
D: Appoint a commission.
Please eliminate two incorrect options first, then think it step by step and choose the most proper one option.