The correct answer is: A. Koklash Pheasant
The Koklash Pheasant is a critically endangered bird found in the Western Himalayas. It is a small, shy bird that lives in dense forests. The IUCN has listed it as critically endangered due to habitat loss and hunting.
The Green-tailed Sunbird is a common bird found in the Himalayas. It is a small, brightly colored bird that feeds on nectar. The IUCN has listed it as least concern.
The Hornbill is a large, colorful bird found in the forests of the Himalayas. It is a social bird that lives in colonies. The IUCN has listed it as vulnerable.
The Bearded Vulture is a large, vulture-like bird found in the mountains of the Himalayas. It is a scavenger that feeds on carrion. The IUCN has listed it as critically endangered.
The Koklash Pheasant is the only bird among the given options that is listed as critically endangered by the IUCN.