Note: The figure shown is representative.

To connect $5$ disconnected land zones ($Z_1, Z_2, Z_3, Z_4, Z_5$), the minimum number of bridges required is $5 - 1 = 4$ (forming a spanning tree of the zone adjacency graph).

Let us determine which zones are separated by each river segment:

• P separates $Z_1$ and $Z_2$

• R separates $Z_2$ and $Z_3$

• Q separates $Z_1$ and $Z_3$

• S separates $Z_1$ and $Z_5$

• T separates $Z_3$ and $Z_5$

• V separates $Z_3$ and $Z_4$

• U separates $Z_4$ and $Z_5$

Now evaluating the options:

• (A) Bridges on P, Q, and T: Uses only $3$ bridges, which is insufficient to connect $5$ zones.

• (B) Bridges on P, Q, S, and T: Connects $\{Z_1, Z_2, Z_3, Z_5\}$, leaving $Z_4$ completely disconnected.

• (C) Bridges on Q, R, T, and V:

  • Q connects $Z_1$ and $Z_3$

  • R connects $Z_2$ and $Z_3$

  • T connects $Z_5$ and $Z_3$

  • V connects $Z_4$ and $Z_3$

  This forms a star graph centered at $Z_3$, connecting all $5$ zones with exactly $4$ bridges (the minimum possible).

• (D) Bridges on P, Q, S, U, and V: Uses $5$ bridges, which is not the least number of bridges.

Therefore, option (C) is correct.