According to the passage, it has long been believed that ______.A．people in poor countries

According to the passage, it has long been believed that ______.

A．people in poor countries scarcely know how to enjoy a high standard of living

B．the world's resources being limited, people in underdeveloped countries are bound to live a poor life

C．most Americans know that the world's resources of many kinds are becoming scarce

D．it is impossible for all the people in the world to improve their living standards