'Epidemics' Are More Likely to Form in Which of the Following

'Epidemics' are more likely to form in which of the following kinds of populations and why?

A) large populations, because there are more people to support the transmission of disease
B) large populations, because they have multiple links between people
C) small populations, because each person is more likely to come in contact with the disease
D) small populations, because the disease needs to infect only a few people to infect the whole population
E) small populations, because disease is more fatal in small groups