John Snow is called the "father of epidemiology because of his work on which disease?

A. Cholera: John Snow investigated the 1854 cholera outbreak in London, tracing the source to a contaminated water pump- a foundational event in epidemiology. B. Malaria: Although significant, malaria was not the focus of John Snow’s work. C. Polio: This was studied later in the 20th century, unrelated to John Snow. D. Smallpox: Edward Jenner is more closely associated with smallpox due to his work on vaccination.