4. Which of the following are caveats that Kazianga et al. (The Effects of "Girl-Friendly" Schools) mention with respect to calculating the cost-effectiveness of the BRIGHT school construction program in Burkina Faso? a. Many of the interventions included in the BRIGHT schools could have affected outcomes other than enrollment and test scores. b. Though the authors have detailed cost information on the BRIGHT schools, their estimates of the cost of the government schools are more tentative. c. They estimate the cost effectiveness of having a BRIGHT school and then add to it the costs that would be incurred in having the unique BRIGHT amenities in a planned government school. d. All of the above