Step 1: Understanding the Concept.
The question wants a single word for how all the people in a society connect and relate to one another, not how they are ranked.
Step 2: Key Formula or Approach.
Sociologists use social structure for the whole web of roles, groups, and relationships in a society, while social stratification is used only for ranking people into layers.
Step 3: Detailed Explanation.
Social structure includes family ties, workplaces, schools, and other groups, along with how they connect to each other. This is the general pattern of relations the question is asking about.
Social stratification instead sorts people by wealth, power, or status into higher and lower layers. It answers a different question, who ranks above whom, not how people relate to each other.
Caste system is just one example of stratification found in Indian society and is far too specific to stand for the whole pattern of relations.
Herd structure belongs to animal grouping behavior, not to human sociology, so it can be ruled out right away.
Step 4: Final Answer.
The correct term for the pattern of inter-relations between persons in a society is social structure.