Introducing Intermountain Basin
The Intermountain Basin is a region characterized by a series of interconnected basins located between the Rocky Mountains and various mountain ranges in the western United States. These basins are known for their unique geographical features and play a significant role in the region's hydrology and ecology.

The Correct Answer: Qaidam Basin
Among the given options, the Qaidam Basin is the correct answer for the Intermountain Basin. Let's explore the characteristics of the Qaidam Basin and understand why it is considered an Intermountain Basin.

1. Qaidam Basin:
The Qaidam Basin is located in western China, specifically in Qinghai province. It is surrounded by mountain ranges, including the Kunlun Mountains to the south, the Qilian Mountains to the northeast, and the Altun Mountains to the northwest. These mountain ranges form a natural boundary around the basin, making it an intermountain basin.

2. Geography and Geology:
The Qaidam Basin spans an area of approximately 120,000 square kilometers, making it one of the largest intermountain basins in the world. It is situated at an average elevation of around 2,800 meters above sea level, making it a high-altitude basin. The basin is primarily composed of sediments deposited over millions of years, resulting in a diverse range of geological formations.

3. Hydrology and Climate:
The Qaidam Basin is a closed basin, meaning it has no outlet for drainage. It is characterized by numerous saline lakes, such as Qinghai Lake, which are fed by rivers and streams flowing from the surrounding mountains. The region experiences a cold desert climate, with low precipitation and extreme temperature variations between day and night.

4. Economic Significance:
The Qaidam Basin is rich in natural resources, including vast reserves of oil, natural gas, and minerals such as salt, potassium, and boron. These resources have played a crucial role in the economic development of the region, with extensive mining and extraction activities taking place in the basin.

Conclusion:
The Qaidam Basin is a prime example of an intermountain basin due to its location between mountain ranges, its closed hydrological system, and its unique geological and ecological characteristics. Understanding the features and significance of the Qaidam Basin helps us identify it as the correct answer among the given options for an intermountain basin.