Concept:Double coincidence of wants is the mutual need in a barter exchange where each party holds what the other wants.
Explanation:In a barter system, money is not used.
Goods are traded directly for other goods.
A trade succeeds only when both parties want each other’s goods at the same time.
The housewife has meat but needs tomatoes.
She must therefore find someone who has tomatoes and also wants meat.
If no such person exists, the exchange cannot take place.
This mutual matching of wants is called double coincidence of wants.
It is a major obstacle to barter trade because finding a perfect match is difficult.
It also explains why money was later introduced to simplify exchange.
Answer:D. Double coincidence of wants.