求教新prep里的一道逻辑题

Early inthe twentieth century, Lake Konfa became very polluted.  Recently fish populations have recovered asrelease of industrial pollutants has declined and the lake’s waters have becomecleaner.  Fears are now being voiced thatthe planned construction of an oil pipeline across the lake’s bottom mightrevive pollution and cause the fish population to decline again.  However, a technology for preventing leaks isbeing installed.  Therefore, providedthis technology is effective, the fears are groundless.

Which ofthe following, if true, most seriously weakens the argument?

A. The pipeline’s construction willdisturb sediments at the bottom of the lake, dispersing into the water toxicpollutants that have settled there.

B.Changes in land use and drainage patternsaround the lake mean that the lake’s waters are increasingly likely to beaffected by agricultural runoff.

C. The leak-preventing technology has been in usefor several years without any pipeline in which it is installed developingserious leaks.

D. Amajor leak of oil from the pipeline would harm not only the lake’s fish butalso populations of other aquatic animalsand plants.

E. Sincethe beginning of the twentieth century, non-native species of fish have beenintroduced into the lake and now make up a considerable proportion of itsoverall fish population.