thE mAin purposE oF thE First pArAgrAph is _________.
A．to show thE mArkEt DEmAnD For FooD supply
B．to show thE worsE living ConDitions oF FArmErs
C．to ExplAin thE rEAson oF FooD shortAgE
D．to ExplAin thE ConFliCt BEtwEEn surplus oF FooD supply AnD rising priCE