H Price in dollars MC-MSC 25 K: 20 15 10 5 0 0 1 2 3 4 5 6 7 8 9 10 11 Smoke detectors (millions per year) Refer the the graph above to answer the following quesitons: a. Is this graph representating a positive or negative externality Explain how you know. (1 points) b. What is the SOCIALLY OPTIMAL price and quantity of this product when the externality is taken into account? (1 points) c. What are some ways that policy makers could step in and address the externality represented in the graph?