ＧＷＤ２８－９应该选A还是选B,奇怪了怎么觉得都对

Early in the twentieth century, laceType>LakelaceType> laceName>KonfalaceName> became very polluted.  Recently fish populations have recovered as release of industrial pollutants has declined and the lake’s waters have become cleaner.  Fears are now being voiced that the planned construction of an oil pipeline across the lake’s bottom might revive pollution and cause the fish population to decline again.  However, a technology for preventing leaks is being installed.  Therefore, provided this technology is effective, those fears are groundless.

The argument depends on assuming which of the following?

1. Apart from development related to the pipeline, there will be no new industrial development around the lake that will create renewed pollution in its waters.


2. Other than the possibility of a leak, there is no realistic pollution threat posed to the lake by the pipeline’s construction.


3. There is no reason to believe that the leak-preventing technology would be ineffective when installed in the pipeline in laceType>LakelaceType> laceName>KonfalaceName>.


4. Damage to the lake’s fish populations would be the only harm that a leak of oil from the pipeline would cause.


5. The species of fish that are present in laceType>LakelaceType> Konfa now are the same as those that were in the lake before it was affected by pollution.

However, a technology for preventing leaks is being installed.

文章结论是provided this technology is effective, those fears are groundless

联系文章的结论和选项, 只有B是ASSUMPTION, A是无关选项

B, A is irrelevant about pipeline construction.

为什么不是C呢，在B和C之间徘徊。觉得B有道理，C也有道理。（assumption题老是令我在两个选项之间徘徊）

C，把NO去掉，就是有理由相信在Lake Konfa里安装管道，漏油科技是无效的

不是正好削弱了原文的结论：提供这个技术是有效的，那些担心是没有根据的

谁能教我鉴别一下？

stimulus concludes: provided this technology is effective, those fears are groundless.

provided functions as "if",it leads a premise.we cant question the premise,so the question whether this technology is effective is irrelative.