Which event increased workers' unrest in Petrograd on 22 February 1917?

Correct answer: A lockout in a factory

The correct answer is A, a lockout in a factory. On 22 February 1917, the management of a factory in Petrograd locked out its workers. A lockout prevents employees from entering or working, so it immediately threatened their wages and livelihoods. Instead of isolating the dispute, the action encouraged workers in other factories to express solidarity, and the unrest grew into wider strikes and demonstrations. The opening of a new parliament, a Tsar’s coronation and a peace treaty were not the events that triggered this stage of the February movement. The governing concept is that an employer’s industrial action can become a political crisis when it occurs amid severe shortages and widespread opposition to the regime.