- Nuclear Family (A): Comprises parents and their offspring; the corresponding characteristic is (II) Mates and their children.
- Matrilineal Descent (B): Kinship is determined via the maternal line; the characteristic is (IV) Offspring belong to the mother's kin group.
- Fraternal Polyandry (C): A woman has multiple husbands, typically siblings; the characteristic is (I) Husbands are Brothers.
- Extended Family (D): Encompasses parents, children, and additional kin like grandparents or aunts/uncles; the characteristic is (III) Married couple and their married children.
Step 1: Concept Alignment.
The accurate pairings are:
- Nuclear Family: Mates and their children
- Matrilineal Descent: Children belong to the kin group of mothers
- Fraternal Polyandry: Husbands are brothers
- Extended Family: Married couple and their married children
Final Answer:
\[
\boxed{\text{The correct answer is (3) (A) - (I), (B) - (II), (C) - (III), (D) - (IV).}}
\]