Correct answer: A. Support of workers soldiers and local representatives
Explanation: The direct answer is A: support from workers, soldiers and local representatives. Soviets were councils or assemblies that claimed to represent ordinary people, especially workers and soldiers, in revolutionary Russia. Their strength came from this grassroots connection and from the ability to organize collective demands and action. Option A is correct because broad support gave the Soviets political influence and a mass base. Option B, support only from the Tsar's family, is wrong because the Soviets opposed the old autocratic order rather than depending on the Tsar's family. Option C, help only from foreign kings, is wrong because their strength was mainly rooted in domestic popular organization, not royal sponsorship. Option D, complete Church control, is wrong because Soviets were political councils, not institutions controlled entirely by the Church. The word “Soviet” can be understood here as a council of representatives. Memory cue: Soviets = workers and soldiers' councils with grassroots support.