题目内容：
Why does the famine in the western Sahara and the Sahel regions of Africa take place this year?
A．People are dying of cancer caused by sprayed insecticide. B．The insecticide has little effect on the hoppers and locusts.
C．The number of the hoppers and locusts are too large to control.
D．The U.N. forbad the regions to use sprayed insecticide.
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答案解析：