The correct answer is D) new customs and ideas are adopted.
What is missing from the diagram showing the relationship between human migration, ideas, and customs is that new customs and ideas are adopted.
People immigrate fro necessity. They need to find better opportunities for them and their family. When they migrate, they take their history, culture, and traditions with them. When they arrive at their new place they encounter different points of view, culture, and traditions that could be very different from theirs. With daily interaction, that is when they share, intermingle or adopt customs, ideas, and concepts from the new country. So the social phenome becomes an interesting case for sociologist on how different people relate to each other, share their beliefs and traditions, learn new ones, and adopt others.