Explanation:

- The Hirakud Dam is built across the Mahanadi River.

- The Saraswati River mentioned in option 1 is a mythical river in Indian mythology and does not host the Hirakud Dam.

- The Godavari River, option 3, is another major river in India, but it does not have the Hirakud Dam.

- The Kaveri River in option 4 is located in southern India, and it is not associated with the Hirakud Dam.

- Option 5, Brahmaputra, flows through northeastern India but is not related to the Hirakud Dam.