The correct answer is: b) Gangtok.
Rumtek Monastery is located in the town of Rumtek, in the East Sikkim district of Sikkim, India. It is the seat of the Karmapa, the head of the Karma Kagyu lineage of Tibetan Buddhism. The monastery was founded in 1966 by the 16th Karmapa, Rangjung Rigpe Dorje. The 17th Karmapa, Ogyen Trinley Dorje, took up residence at Rumtek Monastery in 2000.
Pelling is a town in the West Sikkim district of Sikkim, India. It is a popular tourist destination, known for its views of Kanchenjunga, the third-highest mountain in the world.
Namchi is a town in the South Sikkim district of Sikkim, India. It is the headquarters of the South Sikkim district.
Lachung is a town in the North Sikkim district of Sikkim, India. It is a popular tourist destination, known for its views of the Himalayas.