147. Crops can be traded on the futures market before they are harvested. If a poor corn harvest is predicted, prices of corn futures rise; if a bountiful corn harvest is predicted, prices of corn futures fall. This morning meteorologists are predicting much-needed rain for the corn-growing region starting tomorrow. Therefore, since adequate moisture is essential for the current crop’s survival, prices of corn futures will fall sharply today.
Which of the following, if true, most weakens the argument above?
(A) Corn that does not receive adequate moisture during its critical pollination stage will not produce a bountiful harvest. (缩小了范围，错)
(B) Futures prices for corn have been fluctuating more dramatically this season than last season. （无关比较）
(C) The rain that meteorologists predicted for tomorrow is expected to extend well beyond the corn-growing region. （beyond the corn-growing region无关）
(D) Agriculture experts announced today that a disease that has devastated some of the corn crop will spread widely before the end of the growing season. （可能还有别的因素影响，所以削弱） D
(E) Most people who trade in corn futures rarely take physical possession of the corn they trade. （take the physical possession，无关）
理解d是正确答案，可总觉得a也有道理，如何理解lawyer 给a 的解释？ | 
