Arikamedu is an important archaeological site that provides evidence of:

The correct answer is: a) Indo-Roman trade.

Arikamedu

is an archaeological site located in the Pondicherry district of India. It is a well-known site for its evidence of Indo-Roman trade. The site was excavated in the early 20th century and has yielded a wealth of artifacts, including Roman coins, pottery, and glassware. The evidence from Arikamedu suggests that there was a thriving trade between India and Rome during the early centuries AD.

Option b) Early Buddhist settlements is incorrect. There is no evidence of early Buddhist settlements at Arikamedu.

Option c) Megalithic culture is incorrect. Megalithic cultures are characterized by the construction of large stone monuments, such as dolmens and menhirs. There is no evidence of megalithic culture at Arikamedu.

Option d) Medieval fortifications is incorrect. There is no evidence of medieval fortifications at Arikamedu.