Which of the following pieces of evidence would most support the data’s implication?

(A) In the absence of the virus, the disease has been observed to follow infection by the bacterium.

(B) The virus has been shown to aid the growth of bacterium, a process which often leads to the onset of the disease.

(C) The virus alone has been observed in many cases of the disease.

(D) In cases where the disease does not develop, infection by the bacterium is usually preceded by infection by the virus.（C）

(E) Onset of the disease usually follows infection by both the virus and the bacterium.

why not B?

aid the growth of bacterium,从这里看出来是帮助,就象化学里的催化剂,只是改变速度,没有直接参与反应.

c的理解就是在有些case里,根本没有bacterium的出现,排除了B为原因的可能.是排除他因的加强.

B是说还是bacterium导致疾病，virus是辅助的，原文是说virus导致疾病。C增加virus导致该疾病的可能性，故为答案.