Solve clearly

15. In the paper paper 'Did Highways Cause Suburbanisation what does Baum-Snow use as the instrumental variable? A. Rapid transit plans B. The 1947 National Interstate Highway Plan C. The AMM model D. The National Election 16. According to Duranton & Turner (2011), what is the fundamental law of road congestion? A. When roads become congested, the government should build more roads B. Cities should implement congestion charging C. Roading projects can relieve congestion D. Vehicle kilometres travelled increases one for one with the supply of road kilometres