How did the lockout of 22 February become a revolutionary cause rather than only a factory event?

Correct answer: It turned workers' unrest into open protest

The governing historical concept is the conversion of a workplace dispute into a wider political movement. In Petrograd, the lockout affected workers who already faced shortages, poor working conditions and the pressures of war. Instead of remaining confined to one factory, it added to existing anger and encouraged workers to protest publicly, helping demonstrations spread through the city. It did not increase the Tsar’s popularity, end the First World War or distribute land to peasants. Thus option A correctly identifies the immediate revolutionary significance: the lockout helped transform accumulated labour unrest into collective action.