Concept:The Siachen Glacier is the longest glacier in the Himalayan range.
Explanation:Siachen Glacier lies in the eastern Karakoram range of the Himalayas.
It is located in the Union Territory of Ladakh.
Its length is about 76 kilometres, making it the longest Himalayan glacier.
It is also known as the highest battlefield in the world.
Other options: Machoi Glacier is shorter, Nubra is a river valley, and Rimo Glacier is smaller than Siachen.
Answer:The correct answer is C. Siachen.