98.
     

D
     

Early
in the twentieth century, Lake
                Konfa
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?

B.
There is no reason to believe that the leak-preventing technology would be
ineffective when installed in the pipeline in Lake
                    Konfa.

C. The bottom of the lake does not contain toxic remnants of earlier
pollution that will be stirred into the water by pipeline construction.

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

E.
The species of fish that are present in Lake
                    Konfa
now are the same as those that were in the lake before it was affected by
pollution.

答案是C, 不知道为什么D不对