AP Microeconomics

Answer - A - Excludable is not one of the classifications used for taxes.

Key Takeaway: Taxes are classified in three different ways: progressive, regressive, and proportional. Progressive taxes mean the average tax rate increases as income increases (such as with personal income tax); regressive means that the average tax rate goes down as income increases (examples would be Social Security tax and general sales tax); proportional means that the tax rate remains the same, no matter what the size of the income (like corporate income tax).