Tribal societies in the Mizo hills likely had their own governance systems and social structures during the Vedic and Gupta periods, which might be reflected in:

The correct answer is: d) All of the above

Oral histories and folklore can provide insights into the governance systems and social structures of tribal societies. For example, oral histories may recount the founding of a tribe or the migration of a group of people. Folklore may include stories about the gods or spirits that are important to a tribe, or about the rules that govern social interactions.

Archaeological remains can also provide evidence of governance systems and social structures. For example, the remains of a village or a fort may indicate the presence of a centralized authority. The distribution of artifacts may suggest the existence of social classes or divisions of labor.

Linguistic similarities with neighboring groups can also provide clues about the governance systems and social structures of tribal societies. For example, if two groups speak languages that are similar, it is likely that they share a common history and culture. This may include shared governance systems and social structures.

In conclusion, all of the above (oral histories and folklore, archaeological remains, and linguistic similarities with neighboring groups) can provide evidence of the governance systems and social structures of tribal societies.