The most common medium of exchange in modern economic systems is:

• A. Barter
• B. Gold
• C. Government bonds
• D. Money

Answer: (D)

Verified step by step guidance

1. Understand the concept of a medium of exchange: it is an item widely accepted in exchange for goods and services, facilitating trade by eliminating the inefficiencies of barter.
2. Recall the characteristics of money that make it the most common medium of exchange: it is durable, divisible, portable, and widely accepted.
3. Compare the options given: barter involves direct exchange of goods without a common medium, gold is a commodity money but less practical today, government bonds are financial assets but not used for everyday transactions.
4. Recognize that modern economic systems primarily use money (such as currency and digital money) as the medium of exchange because it efficiently supports trade and economic activity.
5. Conclude that among the options, money best fits the definition and practical use of the most common medium of exchange in modern economies.