- Polygyny is the practice where one man has multiple wives.
- Sororal polygyny refers to a form of polygyny where a man marries two or more sisters.
- Polyandry is the practice where one woman marries multiple men, often seen in some cultures with limited resources where brothers share a wife.
- Group Marriage refers to a system where multiple men and women are all married to one another. Step 1: Understanding Polyandry.
Polyandry is less common but can be observed in some Tibetan and Nepalese cultures. It is practiced to prevent the division of family land and resources. Final Answer:
\[
\boxed{\text{The correct answer is (3) Polyandry.}}
\]