Institutions like the Namgyal Institute of Tibetology in Gangtok house important collections of:

Thangka paintings and manuscripts
Monastery murals and artifacts
Folk art and traditional textiles
All of the above

The correct answer is: d) All of the above.

The Namgyal Institute of Tibetology is a research institute in Gangtok, Sikkim, India. It was founded in 1958 by the 14th Dalai Lama, Tenzin Gyatso, to promote the study of Tibetan culture and religion. The institute houses a large collection of thangka paintings, manuscripts, monastery murals and artifacts, folk art and traditional textiles.

Thangka paintings are a type of Tibetan scroll painting that are used for religious purposes. They are often made on cotton or silk and depict scenes from Buddhist mythology or history. Manuscripts are handwritten texts that are often religious in nature. Monastery murals are paintings that decorate the walls of Tibetan monasteries. They often depict scenes from Buddhist mythology or history. Artifacts are objects that are of historical or cultural significance. Folk art is art that is created by ordinary people for their own use or enjoyment. Traditional textiles are textiles that are made using traditional methods and materials.

The Namgyal Institute of Tibetology is a valuable resource for the study of Tibetan culture and religion. Its collection of thangka paintings, manuscripts, monastery murals and artifacts, folk art and traditional textiles is one of the largest and most comprehensive in the world.