Explanation:

- Kardang Monastery: This is a prominent Drukpa Lineage monastery located in Kardang village, across the Bhaga River in Himachal Pradesh, India. It is known to be one of the largest and oldest monasteries in the Lahaul region.

- Option 1: West Bengal: West Bengal is known for several monasteries, especially in the Kalimpong and Darjeeling areas, but Kardang Monastery is not located here.

- Option 2: Karnataka: This southern state in India has famous monasteries such as Namdroling Monastery, but not Kardang.

- Option 3: Sikkim: Known for its rich Buddhist culture, Sikkim houses various renowned monasteries like Rumtek and Pemayangtse, but not Kardang.

- Option 4: Himachal Pradesh:

This option is correct. Kardang Monastery is indeed situated in Himachal Pradesh.