Explanation:

- The distinction between "family of orientation" (the family into which one is born) and "family of procreation" (the family one forms through marriage and having children) is an important sociological concept.

- Option 1: Warner — An American sociologist, but he is not credited with this particular distinction.

- Option 2: Morgan — Lewis Henry Morgan was an anthropologist, mainly known for his work on kinship and social structure, but not specifically for this term.

- Option 3: Westermarck — Edvard Westermarck focused on marriage and morality, but he did not coin these specific terms.

- Option 4: R.C. Brown — R.C. Brown is the scholar who first made the distinction between family of orientation and family of procreation.

Correct Answer: Option 4 (R.C. Brown)