Answer: C. whether the outbreak is isolated to a region or widespread.
Explanation: When we look into the definitions of both terminologies what we get is,
Epidemic: A widespread occurrence of a particular infectious disease in a community or region.
Pandemic: A pandemic is an epidemic spread over a large geographical area that might include a state, country, or continent.
As the differentiating term in both these terminologies is the area of occurrence of infectious disease so option C which is related to region stands correct.