向前辈们求助一道逻辑题

WilliamUID: 183851

One state adds a 7 percent sales tax to the price of most products purchased within its jurisdiction．This tax，therefore， if viewed as tax on income，has the reverse effect of the federal income tax：the lower the income，the higher the annual percentage rate at which the income is taxed．

The conclusion above would be properly drawn if which of the following were assumed as a premise?

A. The amount of money citizens spend on products subject to the state tax tends to be equal across income levels.

B. The federal income tax favors citizens with high incomes,whereas the state sales tax favors citizens with low incomes.

C. Citizens with low annual incomes can afford to pay a relatively higher percentage of their incomes in state sales tax, since their federal income tax is relatively low.

D. The lower a state`s sales tax, the more it will tend to redistribute income from the more affluent citizens to the rest of society.

E. Citizens who fail to earn federally taxable income are also exempt from the states sales tax.

这道题小弟我是一点头绪都没有，没能理解题干中包含的信息的意思和它们之间的相互关系。看选项更是茫然。希望前辈们能够帮小弟我具体地分析和讲解一下题干和选项，感激不尽。

whoeverioeUID: 170170

题干说sales tax（在购买东西的时候售价加7％税）和federal income tax有相反作用，即收入越低，每年tax占收入的百分比越高。问这个结论是建立在什么假设上
我觉得是a。因为只有各个收入层的人都花一样的钱去买东西，才能导致收入低的人被tax的比较高（in %）