请教: 狒狒笔记的第一课时12题

12. Mercury, one of the deadliest toxins, makes up approximately fifty percent of the amalgam used by dentists in sliver fillings. The effects of acute mercury poisoning are known-kidney failure, muscle tremors, memory loss, and even death. It is clear that responsible dentists should remove all of the patients silver fillings and replace then with filling of plastic composites.
Which of the following, if true, most strengthens the author's argument? 

(A) Sliver fillings gradually corrode and small amounts of mercury leak from the amalgam.
(B) It is difficult to measure the amount of mercury in a person's body.
(C) Some patients have more than one filling per tooth.
(D) Mercury poisoning produces a range of subtle but distinctive symptoms.
(E) The materials for plastic composite fillings are readily available to dentists.

Answer: A

此题归纳为演绎题型的加强类别, 故答案应为加强结论的选项。为何不是E答案？

加强结论有两种形式的加强，在这里并不是单纯的加强结论，而是一种桥梁型的加强，通过答案A将mercury的危害和文章中的结论联系起来。

呵呵，本人的小看法，不知道是否正确：）

E是无关项