Explanation:

- Medium of exchange: Money facilitates transactions by eliminating the need for a barter system. It acts as an intermediary that is accepted by all parties in trade.

- Price stability: Money itself does not ensure stable prices. Price stability is influenced by economic policy and market conditions, not the money's function.

- Store of value: Money can be saved and retrieved in the future, retaining its value over time if inflation is controlled.

- Unit of account: Money provides a consistent measure for pricing goods and services, which helps in comparing value.

Option 2, Price stability, is not a function of money.