Final answer:
A descent group is a permanent social unit whose members claim common ancestry and kinship, essential in determining social norms like inheritance and marriage. Descent can be traced through various systems, such as unilineal, cognatic, or ambilineal, defining one's lineage and social ties.
Step-by-step explanation:
The best definition of a descent group is c-a permanent social unit whose members claim common ancestry and kinship. This group is central to the kinship structure and determines various social elements such as inheritance and marriage rules. There are multiple ways to trace descent, including unilineal descent (through one gendered line), cognatic descent (more inclusively, through both male and female lines), and ambilineal descent (where a single gendered line is chosen, varying by family).
Unilineal descent can further be divided into patrilineal (following the father's line) and matrilineal (following the mother's line). In bilateral descent, individuals trace kinship through both parents, which is the most common form in the United States. Ultimately, descent groups form one's personal lineage, legitimizing certain aspects of social organization.