(a) Discuss the nature of public goods, both pure and impure, and detail how these types of goods might be provided. (b) Consider a proposal, aimed at raising revenue to fund provision of a public good, that involves an increase in the GST (consumption tax) from 10 to 12%. Discuss the efficiency and equity trade-offs associated with such a proposal. Contrast this with the case of raising the marginal tax rate for those earning over $180,000 per annum from 47% to 60%.