In case when social marginal benefit of consumption of some

In case when social marginal benefit of consumption of some good is lower than the demand curve, the tariff:

Solution

Answer : The option number a is correct.

Because when SMB ( Social Marginal Benefit ) curve lies below the demand curve then there occurs negative externality. To control the negative externalities government take some policies and tariff is the one of such government policies which is imposed by the government on imported goods to control the negative externality.