Option 1: Himalayas - The Himalayas is the youngest mountain range in India, formed as a result of tectonic activity between the Indian and Eurasian plates.

Option 2: Aravali - The Aravali mountain range is the correct answer. It is considered to be the oldest mountain range in India, with its formation dating back to around 1.6 billion years ago. The Aravali range extends across the states of Gujarat, Rajasthan, Haryana, and Delhi.

Option 3: Satpura - The Satpura Range is a range of hills in central India. While it is a significant mountain range in the country, it is not the oldest as stated in the question.

Option 4: Nilgiri - The Nilgiri mountain range is located in the southern part of India, specifically in Tamil Nadu, Karnataka, and Kerala. Similar to the Satpura range, the Nilgiri range is not the oldest mountain range in India.

In conclusion, the correct answer is Option 2: Aravali. It is the oldest mountain range in India, formed around 1.6 billion years ago.