The Keibul Lamjao National Park is the only floating national park in the world and is home to the endangered:

The correct answer is: a) Sangai deer.

The Keibul Lamjao National Park is a national park in Manipur, India. It is the only floating national park in the world and is home to the endangered Sangai deer. The park is located on the Loktak Lake, which is the largest freshwater lake in northeastern India. The Sangai deer is a subspecies of the brow-antlered deer. It is a small deer with long, slender legs and a large, forked antler. The Sangai deer is found only in the Keibul Lamjao National Park and in a few other small areas in Manipur. It is an endangered species due to habitat loss and hunting.

The other options are incorrect because:

• The Hoolock gibbon is a species of gibbon found in the eastern Himalayas and southwestern China. It is not endangered.
• The clouded leopard is a species of leopard found in the forests of Southeast Asia. It is not endangered.
• The one-horned rhinoceros is a species of rhinoceros found in the Indian subcontinent. It is endangered.