The correct answer is option 1, Cauvery. In the fifth-century Tamil epic, Silappadikaram, the Cauvery river is praised. The Silappadikaram is a highly revered epic in Tamil literature, and it tells the story of the life and adventures of Kannagi and Kovalan. The Cauvery river is lauded for its beauty and significance in the epic.

Option 2, Godavari, is incorrect as it is not mentioned in the Silappadikaram. The Godavari is a major river in India, but it is not specifically praised in this particular Tamil epic.

Option 3, Saraswati, is also incorrect as the Silappadikaram does not mention this river. The Saraswati river is one of the sacred rivers in Hinduism, but it is not associated with the events or descriptions in the epic.

Option 4, Ganges, is also not the correct answer. While the Ganges is a revered river in Hinduism and is mentioned in many other ancient texts, including the Mahabharata, it is not specifically praised in the Silappadikaram.

Therefore, the correct answer is option 1, Cauvery, as it