An epidemic is the rapid spread of a disease across
a. the world
b. a region
c. a continent
d. oceans

A region is a part on the earth's exterior that has unifying features such as environment or industry. In a city or town, there may be economic or trade areas along with the domestic regions. A good example is in the United States, we generally recognize the Southland as a region.

An epidemic is an outburst of a disease among segments of a particular population that surpasses the extent of the existence of the disease usually found in that population. Epidemics affect those parts of the population who do not have an obtained or innate resistance to the disease. Although maximum epidemics are produced by dangerous organisms, the name can be employed to an outburst of any lingering infection, such as lung cancer or heart disease.