Explanation:

- Controls the entire banking system of the country: The central bank regulates and oversees the commercial banks to ensure stability and compliance with laws.

- Issues currency: It has the exclusive authority to issue and manage currency, ensuring trust and security in the financial system.

- Acts as a banker to the government: The central bank manages the government's accounts, facilitates transactions, and may provide funding when necessary.

- Option 4 - All of these: The central bank performs all these functions as part of its core responsibilities.