蓝皮P5-14

Federal agricultural programs aimed at benefiting one group whose livelihood depends on farming often end up harming another such group.

Which of the following statements provides support for the claim above?

I.                   An effort to help feed-grain producers resulted in higher prices for their crops, but the higher prices decreased the profits of livestock producers.

II.                In order to reduce crop surpluses and increase prices, growers of certain crops were paid to leave a portion of their land idle, but the reduction was not achieved because improvements in efficiency resulted in higher production on the land in use.

III.             Many farm workers were put out of work when a program meant to raise the price of grain provided grain growers with an incentive to reduce production by giving them surplus grain from government reserves.

A)    I, but not II and not III

B)     II, but not I and not III

C)    I and III, but not II

D)    II and III, but not I

E)     I, II and III

我没有理解这个III与原文有个什么关系，没看懂，请教大家