Correct Answer: Income tax

Solution : The correct answer is (a) Income tax

The primary source of revenue for most governments is income tax. Income tax is a tax imposed on individuals and businesses based on their earnings or profits. It is typically levied on various sources of income, including wages, salaries, self-employment income, rental income, investment income, and capital gains.

Income tax is a significant source of revenue because it captures a portion of the income earned by individuals and businesses within a country. Governments often use progressive tax systems, where individuals with higher incomes pay a higher tax rate, while those with lower incomes pay a lower tax rate or may be exempted from income tax altogether.