A social network can be represented as

Question

UnlockIAS · Accepted Answer

A (Graph) or B (Tree) — both are accepted (grace). A social network is a set of people (nodes) joined by relationships (edges), so its natural and most general representation is a GRAPH — that is why option A is correct. Option B, Tree, is also credited because a tree is itself a special kind of graph (a connected, acyclic graph); hierarchical social structures — an organisation's reporting chain, a family tree, a follower/sharing cascade — are trees, and a tree therefore also validly represents a social network. Because both are defensible, the commission accepted either answer.

Why the other options are wrong — (c) Star is a fixed network topology (every node wired to one central hub) borrowed from computer networking — a rigid special layout, not a general model of arbitrary social relationships, so it was not credited.  (d) Ring is a fixed network topology (each node linked to two neighbours forming a closed loop); it cannot capture the many-to-many ties of a social network, so it was not credited.

Concept: In graph theory a graph G = (V, E) is a set of vertices V (nodes) and edges E (links). Social Network Analysis models people as vertices and their ties (friendship, follows) as edges. A tree is a special graph — connected and acyclic (n vertices, n-1 edges, no cycles). Star and Ring are standard physical network topologies.

State PCS 2020 Q58 — Science & Technology PYQ with Answer

State PCS 2020 Q58 — Science & Technology PYQ with Answer