Q1 Externality 5 Points Suppose that the supply curve for Covid-19 vaccinations is horizontal at $25. a. In a diagram, show how the equilibrium for the Covid-19 vaccination quantity differs from the social optimum and explain why. (2) b. In the same diagram, show how a subsidy or a tax could result in the optimal number of vaccinations. Explain. (3) Please select file(s) Select file(s)