Concept:This question tests your ability to arrange jumbled sentences into a logical and coherent paragraph.
Explanation:Start with S1: Prince Lvov's replacement by Kerensky is introduced.
Sentence P directly follows S1 — it explains that this partial replacement did not satisfy the Bolsheviks.
Sentence Q expands on P by stating what the Bolsheviks actually wanted: a soviet of workers, soldiers, and labourers, not a parliamentary republic.
Sentence S comes next — it introduces Lenin's arrival in Russia in April 1917, followed by Trotsky, which is a key development for the Bolsheviks.
Sentence R provides background: Lenin was in Switzerland when the February Revolution broke out. This fits logically before S6, which discusses the existence and role of Soviets in Russia.
The correct sequence is P → Q → S → R, i.e., PQSR.
Answer:Option A: PQSR