Disease surveillance costs $85 per hour as shown by the Supply curve in Figure 15.1. Disease surveillance is a public good. The wealthiest third of the population has a willingness to pay of $200 - Quantity. The middle third has a willingness to pay of $100 - Quantity. The poorest third has a willingness to pay of $100 - Quantity/2. Which of the following statements are true? 1) Willingness to pay is $0 for quantities over 200. 2) The social demand equals the sum of the willingness to pay of the three groups. 3) The efficient point is D. 4) All of the above. 2