The correct answer is: b) Tawang.
Tawang is a town in the Indian state of Arunachal Pradesh. It is the headquarters of Tawang district and is located in the eastern part of the state. Tawang is a popular tourist destination, especially for Buddhist pilgrims. The town is home to the Tawang Monastery, which is one of the largest Buddhist monasteries in the world. The monastery was founded in the 17th century by the Tibetan Buddhist leader Tsangyang Gyatso, who is also known as the Sixth Dalai Lama. The Tawang Monastery is a major pilgrimage site for Buddhists from all over the world.
The other options are incorrect because they are not as significant for Buddhist pilgrimage tourism as Tawang. Eastern Arunachal is a region in the eastern part of Arunachal Pradesh. It is home to a number of Buddhist monasteries, but it is not as popular a tourist destination as Tawang. Lower Subansiri is a district in the eastern part of Arunachal Pradesh. It is home to a number of Buddhist monasteries, but it is not as popular a tourist destination as Tawang. Changlang is a district in the eastern part of Arunachal Pradesh. It is home to a number of Buddhist monasteries, but it is not as popular a tourist destination as Tawang.