Option 1: The construction of a dam across the river Brahmaputra in Tibet is an issue straining Indo-China relations. The river Brahmaputra is a vital water source for both India and China, and any construction that affects its flow or access can lead to tensions between the two countries.

Option 2: The visit of Dalai Lama to Arunachal Pradesh is also another issue straining Indo-China relations. China considers the Dalai Lama a separatist leader and opposes any official visits or interactions with him. When the Dalai Lama visits regions like Arunachal Pradesh, which China claims as a part of its territory, it often leads to diplomatic conflicts between India and China.

Option 3: Stapling of Chinese visa for the people of Jammu and Kashmir is also an issue straining Indo-China relations. China objects to India`s policy of issuing separate visas for residents of Jammu and Kashmir, as it claims a part of the region as its own territory. The stapling of visas is seen as a unilateral action that challenges China`s territorial claims.

Option 4: The linking of Kashmir valley with the Indian Railways Network is not an issue straining Indo-China relations. While there may be other issues surrounding the region of Kashmir, the construction