A regressive tax is one where the tax rate decreases as the individual's income increases. This means that lower-income people pay a higher percentage of their income in taxes than higher-income people. 
Step 1: Tax systems 
- Progressive tax: higher income, higher tax rate. 
- Regressive tax: higher income, lower tax rate. 
- Proportional (flat) tax: same rate for all incomes. 
Step 2: Examples 
Sales taxes and excise taxes are often regressive because they take a larger share from low-income individuals. 
Hence, option (A) is the correct choice.