Explanation:

- Supply of Money: By regulating the amount of money in the economy, the central bank can influence inflation and economic growth.

- Interest Rate: Central banks adjust interest rates to control inflation and stabilize the currency. Lower rates can stimulate borrowing and spending, while higher rates can slow inflation.

- Availability of Money: Ease of access to money through bank lending policies affects consumer spending and business investments.

Correct Answer: 4, All of these

Each component plays a key role in helping the central bank achieve economic stability.