Final answer:
Over 28 million Russian residents belong to non-Russian ethnic groups, accounting for about 20% of the population. This reflects Russia's ethnic diversity with groups like the Tatars and members of former Soviet republics.
Step-by-step explanation:
If we consider that approximately 80% of Russia's population is ethnically Russian, we need to account for the remaining 20% belonging to non-Russian ethnic groups. Given that Russia has a population of over 140 million people, this 20% translates to over 28 million Russian residents who are part of non-Russian ethnic groups, which exceeds the options provided in the question. This diverse demographic includes Tatars, who are the largest minority group making up 3.8%, as well as over 150 other ethnic communities, including indigenous Arctic people and residents from former Soviet republics.
Russia's historical context includes the russification policies which saw a blend of ethnic groups within its borders. Integration and migration have further influenced the ethnic composition, especially after the collapse of the Soviet Union when many ethnic Russians returned to Russia from other post-Soviet states.