Which was a sign of weakening state legitimacy in the February Revolution?

Correct answer: Opposition by Duma leaders and soldiers' mutiny

State legitimacy means the belief that a government has the right to rule and that its commands should be obeyed. During the February Revolution, this legitimacy weakened when Duma leaders openly criticised the government and soldiers refused to defend the Tsarist order, with many mutinying or joining the protesters. These events showed that both political representatives and a crucial instrument of state power, the army, no longer fully accepted the regime. Thus option A is correct. A coronation in option B would normally symbolise continuity, not declining legitimacy. Options C and D describe economic developments that neither occurred as stated nor directly demonstrate the collapse of political obedience.