Agreement with Part B states permits alternative tax collection and financial assistance arrangements subject to time limits and presidential review. Central Government power to enter agreements with States in Part B permitting alternative arrangements for levy and collection of taxes, distribution of proceeds, financial assistance for revenue losses, and state contributions linked to payments under Article 291; such agreements override the chapter's ordinary provisions for that State, may last up to ten years, and may be terminated or modified by the President after five years on consideration of the Finance Commission's report.