prep07和GWD上两道很相似的题目，但是答案却不一样，求大家帮助~

The country of Ertland has never imported apples in any significant quantity because consumers there generally prefer the unique texture of Ertland-grown apples. Nevertheless, apple growers from Kosolia, a neighboring country, plan to sell their apples in Ertland by selling Kosolia-grown apples at half the price of local apples and promoting them as a nourishing, low-cost alternative.

Which of the following, if true, casts most doubt on the viability of the plan by Kosolia's apple growers to sell their apples in Ertland?

• AMost of the varieties of apples grown in Ertland were originally derived from common Kosolian varieties.
• BConsumers in Ertland tend to spend about the same proportion of their income on fresh fruits and vegetables as do consumers in Kosolia.  分析B选项
• CAt times in the past, Ertland has exported significant quantities of apples to Kosolia.
• DSome varieties of apples grown in Kosolia can be harvested throughout most of the year, whereas the varieties grown in Ertland can be harvested only during two months of the year.  
• EProfit of Ertland-grown apples are high enough in Ertland that growers, wholesalers, and retailers there could easily afford to reduce the price at which these apples are sold.
• BG:E国人喜欢吃本地苹果，从来不大量进口别的苹果
• premise: K国的果农计划以本地苹果一半的价格卖K苹果
• conclusion：K国果农认为按照计划他们的苹果会成为一个低廉的替代品打入对方市场
• 所以这道题选E，E国苹果的利润很高，所以卖苹果的人可以很轻易降低苹果的价格，因此K国果农价格战的计划不能成功，weaken原文，这道题我没什么问题
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• GWD5-29
  Overthe past five years, the price gap between name-brand cereals and lessexpensive store-brand cereals has become so wide that consumers have beenswitching increasingly to store brands despite the name brands’ reputation forbetter quality.  To attract theseconsumers back, several manufacturers of name-brand cereals plan to narrow theprice gap between their cereals and store brands to less than what it was fiveyears ago.
  Whichof the following, if true, most seriously calls into question the likelihoodthat the manufacturers’ plan will succeed in attracting back a large percentageof consumers who have switched to store brands?
  A.   There is no significant difference amongmanufacturers of name-brand cereals in the prices they charge for theirproducts.
  B.   Consumers who have switched to store-brandcereals have generally been satisfied with the quality of those cereals.
  C.   Many consumers would never think of switchingto store-brand cereals because they believe the name brand cereals to be ofbetter quality.
  D.   Because of lower advertising costs, stores areable to offer their own brands of cereals at significantly lower prices thanthose charged for name-brand cereals.
  E.    Total annual sales of cereals—including bothname-brand and store-brand cereals—have not increased significantly over thepast five years.
• BG：过去五年名牌谷物和非名牌谷物之间价格差太大，所以即便名牌谷物质量好，人们还是转向购买非名牌谷物
• premise：很多名牌谷物生产者计划把两种谷物之间的价格差缩小到比五年前还低的水平
• conclusion：这一计划可以将这些消费者吸引回来
• 这道题我觉得跟上面那道很像啊，都是希望通过缩小价格差来占据市场。但是这道题选B。我不否认B的确可以weaken，但是有没有谁能给我解释一下为什么不能像上面那题一样选D呢？如果非名牌的谷物也可以降价，那么名牌谷物通过降价的计划就不能实现了吖
• 非常感谢大家~~~
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