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UKMT Junior Kangaroo, 2022

Combinatorics Difficulty 1.0 Junior Find the answer United Kingdom

A map of Wonderland shows five cities. Each city is joined to every other city by a road. Alice's map, as shown, is incomplete. How many roads are missing?

(A) $6$ (B) $5$ (C) $4$ (D) $3$ (E) $2$

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