Biodiversity mainly depends on upon the climatic and geographical conditions available in a particular region. The Western Ghat runs along the western edge of peninsular India. It supports a diverse range of flora and fauna. There are over 6000 vascular plants belonging to over 2500 genera in this hotspot, of which over 3000 are endemic. It is a rich source of spices such as black pepper and cardamom. The highest concentration of species in the Western Ghats is believed to be the Agasthyamalai Hills in the extreme south. The region also harbors over 450 bird species, about 140 mammalian species, 260 reptiles, and 175 amphibians. Over 60% of the reptiles and amphibians are completely endemic to the hotspot.
The Eastern Himalayas is the region encompassing Bhutan, northeastern India, and southern, central, and eastern Nepal. The region is geologically young and shows high altitudinal variation. The Eastern Himalayan hotspot has nearly 163 globally threatened species including the one-horned rhinoceros (Rhinoceros unicornis), the wild Asian water buffalo and in all 45 mammals, 50 birds, 17 reptiles, 12 amphibians, 3 invertebrate and 36 plant species.
So, the correct answer is 'Eastern Himalayas and Western Ghats'