According to the passage, which of the following is true？A．It is very difficult for the mi

According to the passage, which of the following is true？

A．It is very difficult for the middle-aged to live in America.

B．America is Kids Country because the majority of the American population is children.

C．Kids Country was taking shape in America when immigrants poured into the country.

D．America is more of Kids Country than any other countries in the world.