The primary responsibility for preparing the state budget lies with the:

Bihar Finance Department
Chief Minister's Office
Reserve Bank of India
Patna Stock Exchange

The correct answer is: Bihar Finance Department.

The Bihar Finance Department is responsible for preparing the state budget. The budget is a financial plan that outlines the government’s revenue and expenditure for the coming year. It is prepared by the Finance Department in consultation with other departments of the government. The budget is then presented to the state legislature for approval.

The Chief Minister’s Office is responsible for the overall administration of the state. It does not have a direct role in preparing the budget.

The Reserve Bank of India is the central bank of India. It is responsible for managing the country’s monetary policy and regulating the banking system. It does not have a role in preparing the state budget.

The Patna Stock Exchange is a stock exchange located in Patna, Bihar. It is a secondary market for trading shares of companies. It does not have a role in preparing the state budget.