Correct option is B
Effect I: "Many trains on the Katpadi – Chennai route are running several hours late, today."
This is a logical and immediate consequence of the derailment. Since the accident occurred on a significant route, other trains would be delayed due to blockage or repair work on the tracks.
This effect is valid.
Effect II: "Long queues were seen at the railway ticket booking counters in Bangalore."
This does not directly relate to the train accident at Katpadi Junction. Bangalore is geographically distant, and the incident at Katpadi is unlikely to cause a sudden surge in ticket booking queues there.
This effect is unlikely.
Effect III: "Railways has decided to run two holiday special trains between Kolkata and Patna from October to December 2023."
This effect is entirely unrelated to the cause. Running special trains between Kolkata and Patna for holidays has no connection to an accident at Katpadi Junction.
This effect is irrelevant.
Conclusion: Only Effect I is a possible consequence of the train accident.