The B.K. Chaturvedi Committee was set up by the Indian government and it specifically dealt with Price-Reforms in the Oil Sector, making option 4 the correct answer.

To analyze the options further:

Option 1 - Review of Centres-States relations: This is not accurate as the B.K. Chaturvedi Committee was not created to review the relations between the centre and the states.

Option 2 - Review of Delimitation Act: While important, the Delimitation Act, which concerns the fixing of limits or boundaries on political constituencies in India, was not the subject of the B.K. Chaturvedi Committee`s review.

Option 3 - Tax reforms and measures to increase revenues: This is also incorrect. Although tax reforms and revenue measures are critical fiscal issues, they were not the purview of the B.K. Chaturvedi Committee.

Option 4 - Price-reforms in the oil sector: This is the correct answer. The B.K. Chaturvedi Committee`s mandate was to outline a roadmap for pricing and taxation of petroleum products in India.