110. Animals with a certain behavioral disorder have unusually high levels of aluminum in their brain tissue. Since a silicon-based compound binds to aluminum and prevents it from affecting the brain tissue, animals can be cured to the disorder by being treated with the compound.

The argument is based on which one of the following assumptions?

A.        Animals with the disorder have unusually high but invariable levels of aluminum in their brain tissue.

B.        Aluminum is the cause of the disorder rather than merely an effect of it.

C.        Introducing the compound into the brain tissue has no side effects.

D.       The amount of the compound needed to neutralize the aluminum in an animal’s brain tissue varies depending upon the species.

E.        Aluminum is never present in normal brain tissue.

答案时（B）没有问题。

可是（c）选项为什么不对呢。取非后，说明Introducing the compound虽然治好了原来的病，但是同时它带来了副作用，也是不可以使用的。所以是削弱，很正确啊。为什么不选呢？

望高手赐教！