B because it is “pulling” someone away from their home land, making it a pull factor
Answer:Many scholars believe that the collapse of the Indus Valley Civilization was caused by climate change. Some experts believe the drying of the Saraswati River, which began around 1900 BCE, was the main cause for climate change, while others conclude that a great flood struck the area.
Explanation:
I believe its B but i might be wrong IDK