Explanation:

Only statements 1&3 are correct.

• Recently, the Assam Forest Department and conservationists have documented the first photographic evidence of the Mainland Serow (Capricornis sumatraensis thar), in western Assam’s Raimona National Park.

• Himalayan serow ( a subspecies of mainland serow) are typically found at altitudes between 2,000 metres and 4,000 metres. They are known to be found in eastern, central, and western Himalayas, but not in the Trans Himalayan region. 

• Himalayan serow is under the vulnerable category of IUCN Red list.

• The mainland serow’s habitat is across the India-Bhutan border in Phibsoo Wildlife Sanctuary and the Royal Manas National Park in Bhutan. 

Hence option 2nd is correct.