Step 1: Understanding the Question:
The question asks for the definition of the "Nuclear Family" structure.
Step 2: Detailed Explanation:
Sociology classifies families based on structure:
- Nuclear Family: Consists only of the parents and their dependent children (two generations).
- Joint Family / Extended Family: Consists of parents, children, grandparents, uncles, aunts, and cousins living under one roof (multiple generations).
Options (A), (C), and (D) all describe variations of extended or joint families. Option (B) specifically describes the nuclear unit.
Step 3: Final Answer:
A nuclear family consists of parents and their children.