Correct Option (2)
To determine the station that must be passed through when travelling from C to H, all possible routes must be considered based on the given connections.
- From station C, the only outgoing passage is a one-way connection to A (C → A).
- From station A, the only connection is a two-way passage with E (A ↔ E), which implies A → E.
- Consequently, any journey originating from C must proceed through A and then E.
- A viable path from C to H can be established as C → A → E → D → H, utilizing the two-way passage E ↔ D (implying E → D) and the one-way passage D → H.
- Since all routes from C necessarily involve the sequence C → A → E, station E is an unavoidable transit point.
Incorrect Options:
- G: Station G is not a mandatory transit point. A valid path from C to H, such as C → A → E → D → H, does not include G. Therefore, it is possible to reach H from C without passing through G.
- B: Station B is not a mandatory transit point. The path C → A → E → D → H demonstrates that B can be bypassed.
- F: Station F is not a mandatory transit point. The path C → A → E → D → H does not require passing through F.