Mia wants to buy a book. The economic perspective suggests that Mia will buy the book if:

• A. the price of the book is greater than her willingness to pay
• B. the book is a necessity regardless of its price
• C. her consumer surplus is negative
• D. her willingness to pay is greater than or equal to the price of the book

Answer: (D)

Verified step by step guidance

1. Understand the concept of willingness to pay (WTP), which is the maximum amount a consumer is ready to pay for a good or service.
2. Recall that consumer surplus is defined as the difference between the willingness to pay and the actual price paid: \(\text{Consumer Surplus} = \text{WTP} - \text{Price}\).
3. Recognize that a consumer will only buy the good if the consumer surplus is zero or positive, meaning \(\text{WTP} \geq \text{Price}\).
4. Evaluate the given options by comparing them to the economic principle that purchase occurs when \(\text{WTP} \geq \text{Price}\), not when price is greater than WTP or when consumer surplus is negative.
5. Conclude that the correct condition for Mia to buy the book is that her willingness to pay is greater than or equal to the price of the book.