C is the answer theories are like guesses whereas a law is the truth
Well right now there are issues such as unemployment, government corruption, crime, access of clean water, and energy shortages.
In the future there could be issues such as lack of better healthcare treatments and equipment and better education.
The more people that are migrating to urban areas (urbanization) needs more crops for the citizens which causes more people to grow crops and without crop rotating or methods to prevent soil degradation. More likely answer is that more industry grows in the urbanized areas and they have poor management of the soil which causes soil degradation<span />