Answer :
The correct answer is "A".
Civilizations started to appear in a gradual form of throughout history. Numerous discoveries made it possible for mankind to remain in one geographic location, regardless of the seasonal climatic changes this place had.
Discoveries, such as fire, the wheel and further developments to agriculture were the primary factors that led to the creation of establishments, which would later evolve to cities and finally developing traffic of people among them forming an initial civilization.