求问费费逻辑18 least strengthen的含义

cici_head2A

CR刚把资料打出来 还处于入门阶段 做了费费的TEST1 对18题题目不太明白

18. Modern navigation systems, which are found in most of today’s commercial aircraft, are made with low-power circuitry, which is more susceptible to interference than the vacuum-tube circuitry found in older planes. During landing, navigation systems receive radio signals from the airport to guide the plane to the runway. Recently, one plane with low-power circuitry veered off course during landing, its dials dimming, when a passenger turned on a laptop computer. Clearly, modern aircraft navigation systems are being put at risk by the electronic devices that passengers carry on board, such as cassette players and laptop computers.

Which one of the following, if true, LEAST strengthens the argument above?

(A) After the laptop computer was turned off, the plane regained course and its navigation instruments and dials returned to normal.

(B) When in use all electronic devices emit electromagnetic radiation, which is known to interfere with circuitry.

(C) No problems with navigational equipment or instrument dials have been reported on flights with no passenger-owned electronic devices on board.

(D) Significant electromagnetic radiation from portable electronic devices can travel up to eight meters, and some passenger seats on modern aircraft are located within four meters of the navigation systems.

(E) Planes were first equipped with low-power circuitry at about the same time portable electronic devices became popular.

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答案选E 因为E无关 我错选了C 因为感觉题目问的是 LEAST strengthen 我的理解就是能strengthen里面程度最低的 可是显然和答案不符  求问各位NN  LEAST strengthen应该怎么理解呢？strengthen just a little ，not strengthen at all, 还是be irrelevant？
感激不尽呐~~