Final answer:
Siberia refers to Eastern Russia, a vast region extending from the northern Ural Mountains to the Bering Strait, rich in natural resources despite its sparse population.
Step-by-step explanation:
The section of Russia known as Siberia is b) Eastern Russia. Siberia stretches from the northern Ural Mountains to the Bering Strait, covering a vast area larger than the entire United States. While it is home to only about 15 million people, it is rich in natural resources such as oil, timber, diamonds, natural gas, gold, and silver, which are crucial to Russia's economic future. Siberia's key cities lie along major rivers, and the area is famously cold and isolated. Despite the harsh conditions, the economic potential of Siberia remains immense because of its resource wealth.