When we say that money serves as a unit of account, we mean that:

• A. Money provides a common measure for valuing goods and services.
• B. Money can be exchanged for goods and services.
• C. Money is used to store purchasing power over time.
• D. Money facilitates the settlement of debts.

Answer: (A)

Verified step by step guidance

1. Understand the concept of 'unit of account' in economics: it refers to the function of money that provides a standard numerical unit of measurement of the market value of goods, services, and other transactions.
2. Recognize that money serving as a unit of account means it allows us to compare the value of different goods and services using a common measure, making economic calculation and price comparison easier.
3. Distinguish this function from other functions of money such as 'medium of exchange' (money can be exchanged for goods and services), 'store of value' (money stores purchasing power over time), and 'standard of deferred payment' (money facilitates the settlement of debts).
4. Identify that the correct description of money as a unit of account is that it provides a common measure for valuing goods and services.
5. Conclude that the statement 'Money provides a common measure for valuing goods and services' correctly captures the unit of account function of money.