The correct answer is option 1: Pricing and Taxation of Petroleum Products. The Dr. C. Rangarajan Committee is primarily associated with the study and analysis of the pricing and taxation policies related to petroleum products.

Option 2, Estimation of National Income, is not correct. The committee is not specifically involved in estimating national income.

Option 3, TAX structure, is also not correct. Although taxation of petroleum products is part of the committee`s focus, it is not directly related to the overall tax structure.

Option 4, Estimation of Money Supply, is not correct either. The committee`s scope is primarily centered around the pricing and taxation policies related to petroleum products, and money supply estimation is not within its scope of work.

In conclusion, the Dr. C. Rangarajan Committee is associated with the Pricing and Taxation of Petroleum Products.