The lion-tailed macaque (Macaca silenus) is endemic to the Western Ghats, a biodiversity hotspot that spans several states in India, primarily Tamil Nadu, Kerala, and Karnataka. The correct option of 1, 2, and 3 only highlights these states as critical habitats due to their rich forest ecosystems, which provide the necessary conditions for the survival of this species. Andhra Pradesh, while it borders these regions, does not host significant populations of lion-tailed macaques, emphasizing the importance of specific geographical and ecological factors in species distribution. This understanding aligns with UPSC's focus on biodiversity conservation and the significance of protecting endemic species.