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Questions 12 & 13 relate to the following graph: $ Social Cost Private Cost P3 P2 P1 Demand Q1 Qo Quantity 12 The graph best represents: A B C D a. Negative production externality b. Positive production externality c. Negative consumption externality d. Positive consumption externality 13 According to the graph, which price and quantity A B C D combination represents the social optimum? a. P1, Q1 b. P2, Q1 C. P1, Qo d. P2, Qo