Bubonic Plague Is Endemic in Many Countries in Africa and in the Former

Bubonic plague is endemic in many countries in Africa and in the former Soviet Union. This means that:

A) plague was once a huge problem and has now evolved to not cause infection
B) plague has been eradicated from these areas
C) large numbers of people are infected in these areas and it is spreading
D) the disease is always present in the population at a low frequency
E) plague is transferred by human-to-human contact