Which of the Following Statements About Marginal Tax Rates Is

Which of the following statements about marginal tax rates is true?  

A)  A taxpayer's marginal rate can change with every transaction.
B)  As the marginal rate increases, the tax cost of an income-generating transaction decreases.
C)  As the marginal rate increases, the tax savings from a deduction increases.
D)  Both a taxpayer's marginal rate can change with every transaction and, as the marginal rate increase, the tax savings from a deduction increases.