The correct answer is: b) Southeast Asia.
Archaeological evidence suggests that early inhabitants of Arunachal Pradesh had trade links with Southeast Asia. This evidence includes the discovery of artifacts from Southeast Asia in Arunachal Pradesh, as well as the presence of Southeast Asian cultural influences in the region.
For example, in 2003, archaeologists discovered a cache of bronze drums in Arunachal Pradesh that were similar to drums found in Southeast Asia. These drums are believed to have been used for religious ceremonies, and their presence in Arunachal Pradesh suggests that there were cultural and trade links between the two regions.
In addition, the presence of Southeast Asian cultural influences in Arunachal Pradesh can be seen in the region’s art, architecture, and language. For example, the Naga people of Arunachal Pradesh have a tradition of tattooing that is similar to the tattooing traditions of Southeast Asia. The Naga people also have a tradition of building longhouses that are similar to the longhouses of Southeast Asia. Finally, the Naga language has borrowed words from Southeast Asian languages.
All of this evidence suggests that early inhabitants of Arunachal Pradesh had trade links with Southeast Asia. These trade links likely involved the exchange of goods, ideas, and people.