What geographical feature serves as the source of major Russian rivers?

The Valdai Hills is indeed recognized as a significant geographical feature that serves as the source for several major Russian rivers. Located in western Russia, this highland region acts as a watershed area from which essential rivers such as the Volga, the Dnieper, and the Western Dvina originate. The Valdai Hills' elevation plays a crucial role in the hydrology of the region, allowing precipitation to flow into these river systems as they journey toward their outlets.

In contrast, other options listed do not serve as the primary sources for major Russian rivers. The Ural Mountains primarily form a natural divide between Europe and Asia but are not the source for many significant rivers. The Siberian Plateau is a vast area but does not specifically indicate a concentrated source for major river systems. Meanwhile, the Caucasus Mountains are known for a different set of rivers and serve more regional drainage systems rather than being the principal source for the significant waterways found further north. Each of these features plays a distinct role in the geography and ecology of Russia, but the Valdai Hills stand out in terms of being the origin of major rivers in the country.