
Passage: The sewage theory of John Snow, a British doctor, opened the history of epidemiological research. In 1854, when there was a massive cholera outbreak in London, John Snow found that most of the deaths had drunk water from the same pump, while people using other pumps or wells were not initially infected with cholera. After investigation, sewage from the sewer contaminated the pump, causing cholera.
Question: Which of the followings is a method or principle that John Snow's reasoning does not apply?
A. A.The factors that exist in every situation where the phenomenon is studied are likely to be the cause of the phenomenon
B. B.The factors that do not appear in all situations where the subjects do not appear are probably not the cause of this phenomenon
C. C.When the subject changes, the factor of synchronous quantitative change is likely to be the cause of this phenomenon
D. D.The initiative between the situations where the subjects appear and the situations where the phenomenon does not occur is likely to be the cause of the phenomenon
Answer: