【单选题】

Economically, the world can be divided into two parts. The difference between them is that one part is poor and the other is wealthy. In the poor countries of the world, a lot of people never get enough to eat. In the wealthy countries, a lot of people eat too much. The tragedy is that there are more people in the poor countries than there are in the wealthy countries. It is estimated that about 80% of the world’s population cannot afford to have proper food, housing or medical care. The poorer countries are often referred to as the Third WorlD、They have special problems. Often their land is too poor to grow anything on. The land can be improveD、But a lot of things have to be done first, new farming methods have to be introduced, people have to be educated, and reliable sources of water and energy have to be founD、

Many of these problems are too complex for one country to solve alone. Outside help is needed, but it has to be the right kind of help. Money is not enough. Newly developed countries need to be helped to be able to help themselves.
The last word of this passage "themselves" means "______".
A、newly developed countriesB、rich countries
C、developing countriesD、developed countries