As cities continue to expand and grow, residents most likely can expect
a. less urban sprawl
b. less smog and haze
c. less air pollution
d. less availability of water

Less availability of water

 I would say D. Because as more people move into the city there is less water 

Geothermic gradient is the rate of increasing temperature with respect to increasing the depth in the earths interior. away from tech tonic plates boundaries, it is about 25-40 c/km (72-87 degrees f/mi) of depth near the surface in most of the world.