The Northern end of which among the following sanctuaries adjoins the Doda district of Jammu and Kashmir?

The correct answer is: Kalatop Khajjiar.

The Kalatop Khajjiar Sanctuary is a protected area in the Indian state of Jammu and Kashmir. It is located in the Doda district, and is bordered by the Chamba district of Himachal Pradesh to the north. The sanctuary is home to a variety of wildlife, including snow leopards, Himalayan tahr, and musk deer. It is also a popular tourist destination, known for its scenic beauty.

The other options are incorrect because they are not located in the Doda district of Jammu and Kashmir. Gamgul is a village in the Kishtwar district, Tundah is a village in the Ramban district, and Kugti is a village in the Udhampur district.