问题详情

According to the last paragraph, the author tried to tell us ______.
A．the United States is difficult to be unified
B．the United States is a big melting pot in which you can be melt into death
C．the United States is a single, unified nation in which it includes the immigrants all over the world
D．in the United States you can find your previous identities请帮忙给出正确答案和分析，谢谢！