Consider the following statements regarding the Vijayanagar empire:
1. It was named after the city of Vijayanagara.
2. Krishnadeva Raya was the greatest of all the Vijayanagar rulers.
3. Kings of Vijayanagar ruled on behalf of Shaivite deity Virupaksha.
4. Vijayanagar empire successfully resisted the march of the Delhi Sultans to the south.
Which of these statements are correct?