Answer:
For Mark, Sue and Fred would be his family of orientation.
Explanation:
The family of orientation is the family that raises an individual. The individual can be adopted or biologically related to the family members. The family of orientation plays a major role in maintaining the well-being, providing safety, enculturation and socialization of the individual.
The family of orientation can be the biological parents, siblings, relatives, grandparents or stepfamily.
Therefore, for Mark, Sue and Fred would be his family of orientation.