Historically, which type of tax has been the largest source of revenue contribution to the Union Government's budget from indirect taxes?

Which of the following is an example of a direct and progressive tax in India?

Which of the following statements regarding the Principles of Taxation are correct? I. The principle of certainty emphasizes that the amount, time, and method of tax payment should be clear, helping to prevent corruption and build trust. II. The principle of economy dictates that the administrative cost of collecting taxes should be kept as low as possible compared to the revenue generated. III. The principle of elasticity ensures that tax revenue increases automatically with economic growth, without requiring major changes in tax rates. IV. The principle of diversity suggests that a tax system should rely on a single, highly productive source of tax to spread the tax burden effectively.