The correct option is "1 only" because the Asiatic lion (Panthera leo persica) is endemic to the Gir Forest in India and is not found in the wild elsewhere, making its presence unique to the country. In contrast, double-humped camels (Camelus bactrianus) are primarily found in Central Asia, particularly in regions like Mongolia and China, while the one-horned rhinoceros (Rhinoceros unicornis) also has populations in countries like Nepal and Bhutan beyond India. This distinction highlights India's unique conservation challenges and biodiversity significance, a critical topic in UPSC Prelims GS Paper I regarding environmental geography and wildlife conservation efforts.