QUESTION 16 Which of the following is NOT an example of an activity that generates positive externalities? O A. Investments in public health that reduce the transmission of communicable diseases. O B. Working together and learning from each other when completing a homework assignment. O C. Driving on congested highways during peak demand times ofthe day. O D. Firms making research and development (R&D) investments in discovering new technologies. QUESTION 17 During a global pandemic, face-to-face social interactions have important negative externalities. What does this mean in terms of the relationship between the private and social costs of social interactions? O A. Average private costs of social interactions during a pandemic are larger than the marginal social costs. O B. Average private costs of social interactions during a pandemic are smaller than the marginal social costs. O C. There are no negative externalities of social interactions in a pandemic. O D.Average private costs of social interactions during a pandemic are equal to the marginal social costs. QUESTION 18 Which of the following statements characterizes the findings of Devoto et al. (2012) on water connections in urban Morocco? O A. Poor households that received water connections had improved water quality. O B. There was essentially no benefit. O c. The poor who received water connections had more time to spend on other activities besides fetching water, improving their quality of life and perceived happiness. O D. Poor households that received water connections had better health outcomes