Q31:

Which of the following most logically completes the argument below?

Davison River farmers are currently deciding between planting winter wheat this fall or spring wheat next spring. Winter wheat and spring wheat are usually about equally profitable. Because of new government restrictions on the use of Davison River water for irrigation, per acre yields for winter wheat, though not for spring wheat, would be much lower than average. Therefore, planting spring wheat will be more profitable than planting winter wheat, since‗‗‗‗‗‗.

the smaller-than-average size of a winter wheat harvest this year would not be compensated for by higher winter wheat prices 虽然是答案，但让人不能理解

new crops of spring wheat must be planted earlier than the time at which standing crops of winter wheat are ready to be harvested the spring wheat that farmers in the Davison River region plant is well adapted to the soil of the region 开始选的是这个答案，后来发现是无关选项

spring wheat has uses that are different from those of winter wheat planting spring wheat is more profitable than planting certain other crops, such as rye

有没有哪位好心人帮我讲讲啊

B, C, D, E are all irrelevant, so only A is left.

The question is asking for an evidence that can support the conclusion. This is a variation of assumption question. You can try deny test.

Deny A, we get "the smaller-than-average size of a winter wheat harvest this year would be compensated for by higher winter wheat prices". If so, the conclusion "planting spring wheat will be more profitable than planting winter wheat" will fall apart. Therefore, A is an necessary evidence -- A is the best answer.