Based off my BROAD knowledge of world history (as in, sorry if I'm wrong), I believe the answer is B and C.
I think Europeans more tried to change Native culture to be more European, so I eliminated A and D.
I know population did increase in Europe with the introduction of new crops, like tomatoes, corn, and potatoes being introduced. Potatoes were easy to grow, pretty much making Ireland dependent on it at the time. So I think B is correct.
Europeans did move to the Americas, sometimes to avoid religious prosecution, sometimes to start a new life because they were poor, or otherwise. Overpopulation could have also been a reason, so that's why I think C is correct.
Hope I helped.