Why Correct: The concessive clause introduced by "although" must come first, followed by the subject and verb of the main clause. The sequence (Q)(P)(S)(R) forms: "It has been established that although Einstein was a great scientist, he was weak in arithmetic right from his school days." This is grammatically complete and logical. The phrase "right from his school days" modifies the verb "was weak" and sits after it.
Distractor Analysis: Starting with (Q)(P)(R)(S) yields "although Einstein was weak in arithmetic right from his school days" — a fragment that lacks a main clause after the concessive opener. The sequence (P)(R)(S)(Q) gives "Einstein was weak in arithmetic right from his school days although a great scientist" — the verb "was" is missing before "a great scientist," leaving the clause incomplete. The sequence (P)(S)(Q)(R) produces "Einstein was right from his school days although a great scientist weak in arithmetic" — the adverbial phrase interrupts the subject-verb connection and the adjective phrase is misplaced.
Takeaway: In a concessive construction, "although" introduces a subordinate clause that contrasts with the main clause; the main clause must contain its own finite verb. Adverbial phrases of time such as "right from his school days" typically follow the verb they modify, not the subject.