Between 1860 and 1900, a primary cause of migration from rural to urban areas was

B and A

Explanation:

The Native American tribes were the only ones that really needed hunting grounds in early america. This is also way they refused to leave their land. It was there sacred ground they kept for generations and it was being forced out of them by white settlers. They didn't want to go to war with Americans because they knew they were going to lose so they stayed in their land as long as possible until thrown out or killed.