Final answer:
The highest peak in South America is Mount Aconcagua, with an elevation of 22,841 feet, making it the correct answer to the question.
Step-by-step explanation:
The highest mountain peak in South America is Mount Aconcagua. Option A, Mount Aconcagua, stands at 22,841 feet in elevation and is located in Argentina. It is indeed the tallest peak in the Western Hemisphere. In contrast, Mount Kilimanjaro, mentioned as option B, is Africa's tallest mountain with an elevation of 19,340 feet, and it cannot be the highest peak in South America. Option C, Mount Everest, is the world's highest peak at 29,035 feet but is located in Asia.
Lastly, Mount Denali, known as Mount McKinley, is the highest peak in North America and stands at 20,310 feet, ruling out option D. Therefore, Mount Aconcagua is the correct answer to the question regarding South America's tallest mountain peak.