Answer:
C. market failure occurred; the deadweight loss is reduced
Step-by-step explanation:
Carbon emissions produce externalities: they affect others not involved in the transaction, in the form of pollution, or in the form of contributions to climate change. Externalities are a form of market failure because in this situation, the market fails to allocate resources in a way that produces the best social benefit (the Pareto Optimum).
To correct the externality, a tax is imposed, this type of tax is known as a Pigouvian tax. The Pigouvian tax reduces the deadweight loss caused by the externality.