Final answer:
Mount Whitney is located in the Sierra Nevada mountain range, which extends across California and is the result of ancient volcanic activity and recent topographic changes.
Step-by-step explanation:
Mount Whitney, the highest peak in the lower 48 states, is located in the Sierra Nevada mountain range. This range runs 400 miles across the middle of California and is known for its massive granite batholiths, which were formed by subduction-related volcanic activity during the Late Mesozoic era, much like the Rocky Mountains. However, the Sierra Nevada's significant topography is relatively recent, developing within the last 5 million years due to extensional stress. In contrast, the Rocky Mountains were formed during the Laramide Orogeny and have been weathered and eroded over time. The Cascade Range is characterized by its active volcanoes and modern subduction processes. Thus, for the question, the correct answer is option b) Sierra Nevada.