The correct answer is Push factor, because people left Russia to escape dangerous conditions.
In the late 1800s, many Russian Jews immigrated to the U.S. to escape mistreatment in their native country, which is an example of the Push factor, because people left Russia to escape dangerous conditions.
A Push factor regarding immigration is when people move in a voluntary way because there would be a risk if they stayed. What is considered a Push Factor is a war, famine, internal conflicts, and drought. Such is the case of many Russian Jews immigrated to the U.S. to escape mistreatment in their native country. They escaped their native cities for the dangerous conditions they lived there.