Question: Suppose the United States were to convert its tax system from an income tax to a national sales tax on sales of goods and services. Certain necessities, like food, would be exempted from taxation, and low-income households would be granted tax refunds. Would such a tax system eliminate incentives to shift activities
(a) from one period to the next,
(b) from one type to another, and
(c) from one pocket to another?