The correct answer is C) environment and geography.
The two main factors that influenced the development of humans were the environment and geography.
Humans were nomads, gather-hunters that followed herds to hunt them in order to survive. But during the Neolithic Revolution or Agriculture Revolution, they learned agriculture techniques that allowed them to settle in one place. The firsts ancient civilizations could flourish due to the environmental conditions that helped them and geography. They needed good weather and fertile soil to grow crops. For instance, that is what happened with the Sumerian civilization that settled in between the Tigris and Euphrates Rivers in the Middle East. Thet founded important city-states such as Uruk, Kish, Ur, or Lagash.
The other options of the question were A) environment and rivers. B) geography and ice ages.