Who played the leading role in defending Bolshevik power during the Russian Civil War?

Correct answer: The Red Army

The governing concept is the military consolidation of Bolshevik power after the October Revolution. The Red Army, organised under the Bolshevik government and associated with leaders such as Leon Trotsky, fought the anti-Bolshevik White forces during the Civil War. Its military organisation, recruitment, and control of important areas helped the Bolsheviks retain power. Option A is correct because the Red Army was the principal force defending the new revolutionary government. Britain and France intervened in support of anti-Bolshevik forces in parts of Russia rather than defending Bolshevik rule. The Tsar’s army had already been destroyed as an institution after the revolution, so D is also incorrect.