Which of the following sentences is the main idea of this passage？A．Children in the Old Co

Which of the following sentences is the main idea of this passage？

A．Children in the Old Country are not as happy as their counterparts in America.

B．America is a country in which the concept of children is more emphasized than any other countries in the world.

C．Adults in America are becoming increasingly useless.

D．Adults should learn from their children because they are more energetic.