To buy a product, customers in a market must first:

• A. receive a subsidy from the government
• B. have a willingness to pay that is at least equal to the market price
• C. own shares in the company selling the product
• D. be informed of the producer's cost of production

Answer: (B)

Verified step by step guidance

1. Understand the concept of 'willingness to pay' (WTP), which represents the maximum amount a consumer is ready to pay for a product or service.
2. Recognize that for a consumer to actually purchase a product, their willingness to pay must be at least equal to the market price of the product; otherwise, buying the product would not be beneficial to them.
3. Note that receiving a subsidy, owning shares, or knowing the producer's cost are not necessary conditions for a consumer to buy a product in a typical market transaction.
4. Therefore, the key condition for a purchase is that the consumer's willingness to pay (WTP) satisfies the inequality: \(\text{WTP} \geq \text{Market Price}\).
5. This ensures that the consumer gains utility or satisfaction from the purchase that is at least as great as the cost they incur, motivating the purchase decision.