The correct answer is (a). Gurushikhar is situated in the Aravali Range. The Aravali Range is a mountain range in northwestern India. It is the oldest mountain range in India and is about 500 million years old. The Aravali Range runs from the Aravalli Hills in Rajasthan to the Delhi Ridge in Haryana. The highest peak in the Aravali Range is Gurushikhar, which is located in Rajasthan. Gurushikhar is a sacred mountain for Hindus and is said to be the place where the Hindu god Vishnu meditated.
The other options are incorrect. The Assam Himalaya is a mountain range in northeastern India. The Vindhyan Range is a mountain range in central India. The Satpura Range is a mountain range in central India.