The correct answer is B) Arunachal Pradesh. Bum La Pass is a mountain pass located in the Himalayas. It serves as a border pass between India and China. On the Indian side, it is situated in Tawang district of Arunachal Pradesh. Bum La Pass is historically significant as the location where the Dalai Lama crossed into India in 1959 to seek refuge. It is also one of the designated Border Personnel Meeting (BPM) points between the Indian Army and the People’s Liberation Army of China.