Answer:
regressive
Explanation:
A regressive tax is basically a tax whose rate increases as your income decreases. Generally you do not need to increase the marginal tax rate of lower income levels, all you need to do is have a flat tax that taxes everyone with the same amount. E.g. everyone pays $2,000 as income taxes. $2,000 per person represents 10% of the first household's income, but it only represents 2.7% of the fourth household's income.
On the other hand, progressive taxes increase as the income level of the taxpayers increases.