Correct : c

The correct answer is Option C - Bridges on Q, R, T, and V.
This is a graph theory problem in disguise. The 5 zones Z1–Z5 are nodes, and each river segment that separates two zones is a potential edge. To connect all 5 zones with the minimum number of bridges, we need a spanning tree - which for 5 nodes requires exactly 4 edges (bridges).
Options A (3 bridges) and B/D (4–5 bridges) are either insufficient or redundant. Option C with bridges on Q, R, T, and V provides exactly 4 bridges that form a spanning tree connecting all 5 zones without any cycle. This is the minimum needed to ensure every zone is reachable from every other zone.
The key formula - to connect n zones with minimum bridges, you always need exactly n−1 bridges. With 5 zones, that''s 4 bridges. Option C is the only set of 4 bridges that successfully connects all zones.