The answer could be B. The Loss of Biodiversity
Because of the growing population of the city, there is a tendency that they city would widen its territory by land expansion, for areas that have large forest nearby, there is a possibility that people would cut trees and try to urbanize the area. In turn, animals would be displaced. There is a big possibility that animals would try to run to urban centers to hunt or find a new habitat because their habitat was destroyed by the growing human population.