In this sentence arrangement question, four labelled sentences P, Q, R, and S are given; when properly sequenced they form a coherent paragraph about Mohanlal arriving in Kolkata at midnight, and you must choose the most logical order.

Introduction / Context:
This question belongs to the sentence arrangement or para-jumbles category. Four labelled parts P, Q, R, and S are given, and you must arrange them in an order that forms a clear, logical, and coherent short narrative. The passage here describes the experience of a man named Mohanlal whose train reaches Kolkata late at night. Understanding the natural flow of time and events is essential to solving this type of question.

Given Data / Assumptions:
- R: Mohanlal's train was late and it reached Kolkata a little after midnight.
- Q: It was his first visit to the city and he did not know where to go.
- S: He thought he would go to a choultry where he would not have to pay rent.
- P: But he did not know how to find one at that hour.
- Only one sequence of these four sentences will produce a smooth and logical paragraph.

Concept / Approach:
In para-jumble questions, look for the best opening sentence, which usually introduces the main character, place, or time. Then follow the natural progression of events. Here, the story revolves around a late-running train, Mohanlal's unfamiliarity with Kolkata, his idea of staying at a choultry, and the problem of locating it late at night. We must order the sentences so that each new sentence logically follows the previous one without breaking the narrative flow.

Step-by-Step Solution:
Step 1: Sentence R mentions that Mohanlal's train reached Kolkata after midnight, introducing the character, location, and time. This is a natural opening. Step 2: After arriving late, it makes sense to mention that it was his first visit and he did not know where to go, which is stated in Q. Step 3: Next, once his confusion is established, he considers a solution. Sentence S says he thought of going to a choultry where he would not have to pay rent. Step 4: Finally, P explains the difficulty with this plan: he did not know how to find such a choultry at that late hour. Step 5: Therefore, the logical order is RQSP.

Verification / Alternative check:
Check alternative sequences quickly. Starting with Q does not work well, because it refers to "It was his first visit" without specifying where or when. Starting with S or P would be abrupt, since they mention "he" and "one" without prior context. Only R can serve as a smooth entry point to the story. Once R is placed first, Q naturally follows, and S and P must come after, with S describing his idea and P describing the problem in executing that idea. Thus, RQSP is the only sequence that results in a coherent paragraph.

Why Other Options Are Wrong:
PSQR starts with "But he did not know how to find one at that hour", which uses "But" and "one" without any previous statement, so it feels incomplete. QRSP begins with "It was his first visit to the city" without specifying that he has just arrived at midnight. RSQP is also awkward, because placing S immediately after R and then Q breaks the order of thought and confusion. Only RQSP maintains clear chronology and logic.

Common Pitfalls:
A frequent mistake is ignoring pronouns and linking words like "But", which usually refer back to something already said. Another error is failing to identify the sentence that clearly sets up the context, such as arrival time and place. When solving para-jumbles, always look for the sentence that can logically begin the passage and then follow the cause-and-effect or time sequence.

Final Answer:
The most logical and coherent sequence of the sentences is RQSP.