Roman settlement and factory have been discovered at Arikamedu.

Explanation:
Arikamedu is the correct answer as it is the site where a sizable Roman settlement and a Roman factory have been discovered.

- Location: Arikamedu is located near the modern-day city of Puducherry in southern India. It is situated on the banks of the Ariyankuppam River, which was a major trade route during ancient times.

- Roman Trade: Arikamedu was a significant port during the ancient period and played a crucial role in the maritime trade network of the Roman Empire. The Romans established trade relations with various regions in India, and Arikamedu emerged as an important center for the exchange of goods.

- Archaeological Discoveries: Excavations conducted at Arikamedu have revealed the presence of Roman artifacts, pottery, and structures, indicating a strong Roman presence in the area. These findings include Roman amphorae (ceramic jars), coins, beads, glassware, and other objects of Roman origin.

- Roman Settlement: The discovery of residential structures, such as foundations of houses and Roman-style brick walls, suggests the existence of a sizable Roman settlement at Arikamedu. The layout of the settlement indicates a planned urban area with streets and buildings.

- Roman Factory: Along with the residential area, the excavation also revealed the remains of a Roman factory at Arikamedu. This factory was involved in the production of various goods, including beads, gems, semi-precious stones, and textiles, which were highly sought after in the Roman Empire.

- Trade Network: The presence of the Roman settlement and factory at Arikamedu highlights the extensive trade network between the Roman Empire and ancient India. It signifies the exchange of not only goods but also cultural influences between these two regions.

In conclusion, Arikamedu is the port where a sizable Roman settlement and a Roman factory have been discovered. The archaeological findings at this site provide valuable insights into the ancient maritime trade and cultural connections between the Roman Empire and India.