Which of the following will cause an increase in consumer surplus?

• A. A decrease in the number of consumers in the market
• B. An increase in the market price of the good
• C. A decrease in consumers' willingness to pay
• D. A decrease in the market price of the good

Answer: (D)

Verified step by step guidance

1. Recall that consumer surplus is the difference between what consumers are willing to pay for a good and what they actually pay. It is graphically represented as the area below the demand curve and above the market price.
2. Understand that consumer surplus increases when the market price decreases because consumers pay less while their willingness to pay remains the same or higher, increasing the area between the demand curve and the price line.
3. Analyze each option: a decrease in the number of consumers reduces total consumer surplus since fewer consumers are buying; an increase in market price reduces consumer surplus because consumers pay more; a decrease in willingness to pay lowers consumer surplus as consumers value the good less.
4. Identify that a decrease in the market price of the good leads to an increase in consumer surplus because consumers pay less for the same good, increasing the difference between willingness to pay and actual price.
5. Conclude that the correct answer is the decrease in the market price of the good, as it directly increases consumer surplus by expanding the area between the demand curve and the price consumers pay.