What’ s the main idea of the story? 这个故事的中心思想是什么?
选项：

A: Help others, and you will feel happy. 帮助别人,你就会感到快乐。
B: It ’ s necessary to write letters to poor children.
C: Live a simple life, and you can give others help.
D: It ’ s the most important to help the children in Africa.