To What Does the Term Segregation Refer

To what does the term segregation refer?

A) Combining a majority and a minority group through intermarriage.
B) Physically separating two groups; it is often imposed on a minority group by a dominant group.
C) Denying opportunities and equal rights to individuals and groups because of prejudice or for other arbitrary reasons.
D) Deliberately and systematically killing the members of an ethnic, racial, or nationality group.