Which of the Following Defines a Population

Which of the following defines a population?

A) It is any well-defined group of people or things about which researchers want to know something.
B) It is a well-formed group of people who share the same ethnicity, race, and social status.
C) It is any well-defined group of people who are related to each other by a common language or religion.
D) It is a group of people who are spread across the world but would help each other in the time of crisis.
E) It is any group of things that remain unchanged for a particular time period.