Answer:
Individual income taxes
Step-by-step explanation:
Individual income taxes also known as personal income taxes, are taxes levied on personal income/wages of employees by the government. this is a primary source of revenue for the Government because all level of the Government levies individual income taxes on employees on under their jurisdiction and it is also a primary source because every Government have employees working in the system either in public or private sector.
Government charges Customs duties on imported goods and services and this can be levied only by the Federal Government and in countries where Import is been made and other levels of Government cannot charge this. also social security payroll taxes are withheld on behalf of the Federal Government and borrowing is not the primary source of revenue as well.