Answer:
d. ethnic group .
Explanation:
Ethnic group -
It is the type of group , where the people are characterized by the similarity of language , culture , nation , society , ancestors etc , are referred to as a ethnic group .
The term ethnicity , is the inherited status by the ancestors , which get carried forward . The people of same ethnic group have same language , religion , ancestry , cultural heritage , origin and myths .
Hence , the statement given in the question , is about ethnic group .