Why was the cavalry's refusal to fire on demonstrators decisive?

Correct answer: It weakened the government's ability to repress

The governing historical concept is the role of military loyalty in sustaining or weakening an authoritarian regime. During the February Revolution in Petrograd, the refusal of soldiers to fire showed that the Tsarist government could no longer rely fully on the armed forces for repression. This encouraged demonstrators, strengthened the strike movement, and helped convert unrest into a wider political crisis. Therefore option A is correct: the government’s coercive capacity was weakened. Option B is the opposite of what happened. Option C is incorrect because workers’ demands continued and became more politically powerful. Option D is also wrong because the Duma’s position was not automatically determined by one refusal to fire. The army’s changing attitude was a decisive turning point.