Barter is a direct exchange of goods or services without using money

Steps:

• Define barter as a transaction where goods or services are swapped directly, excluding any monetary payment.
• Review each option to check for money involvement or pure exchange.
• Identify options with no cash as barter; those with cash as not barter.
• Confirm B involves negotiation leading to a cash purchase, not exchange.

Why B is correct:

• Barter requires no money; B is a monetary sale at a discounted price, per standard economic definition of barter as non-monetary trade.

Why the others are wrong:

• A: Direct swap of car service for plumbing work, no money involved.
• C: Exchange of textbooks for a radio between students, pure goods swap.
• D: Mutual advertising rights granted without cash, a service-for-service barter.

Final answer: B