The correct answer is A.
A regressive tax is applied uniformly to all taxpayers. Therefore, every person pays exactly the same, but such payment means a higher burden for those taxpayers with a lower income. If you earn 100, paying 1 as tax doesn't mind a lot to you, but if you earned 10 it would mind much more.
The most important regressive tax is the value added tax (VAT), in which a certain percentage of the price paid for a product is charged on top as a tax. If you buy rice, the percentage charged as VAT is the same for all consumers, but that amount of money would mean more to a humble shop owner than to the US president, for example.
