Man can not go on increasing his number at the present rate. In the （ 1 ） 30 years man will face a period of crisis.__（ 2 ）__ experts believe that there will be a widespread food shortage.Other experts think this is too pessimistic, and that man can prevent things from getting worse than they are now. But remember that two thirds of the people in the world are under-nourished（有营养的）or starving now. One thing that man can do is to limit the （ 3 ） of babies born. The need （ 4 ） this is obvious, but it is not （ 5 ） to achieve. People have to be persuaded to limit their families. 根据短文内容，在A、B、C、D、E五个选项中，选出最佳答案填入文中【5】处。（）
A for B easy C Some D number E next