The correct answer is "1 only" because Srisailam, renowned for its Shiva temple, is indeed located in the Nallamala Hills, which is a significant geographical and cultural region in Andhra Pradesh, known for its dense forests and spiritual significance. Conversely, Omkareshwar is situated in the Mandhata Island of the Mandhata Hills, and Pushkar is located near the Aravalli Range rather than the Mahadeo Hills. Understanding the geographical contexts of these pilgrimage sites is essential for UPSC aspirants, highlighting the relationship between geography and culture in Indian heritage.