Why did foreign intervention prevent the Russian Civil War from remaining only an internal conflict?

Correct answer: It connected anti Bolshevik sides with external support

The direct answer is A: foreign intervention connected anti-Bolshevik forces with outside support. After the October Revolution, the Civil War was fought mainly between the Red Army and several anti-Bolshevik groups, often called the Whites. Some foreign powers sent troops, weapons, money, or other help to forces opposing the Bolsheviks. Therefore, the conflict was not only a struggle among people inside Russia; other countries also became involved. Option A is correct because it clearly describes this outside connection. Option B is wrong because intervention did not give peace; it made fighting more complicated. Option C is wrong because intervention did not restore Tsarism. Option D is wrong because the Red Army was not ended; it continued fighting and eventually defeated its major opponents. Remember: foreign troops or aid mean that a civil war has acquired an international dimension.