Among which of the three dynasties was the 'Tripartite struggle', the long-drawn-out conflict over Kanauj, fought?
1. Gurjara-Pratihara, Pala and Chola
2. Rashtrakuta, Chola and Pala
3. Gurjara-Pratihara, Rashtrakuta and Chola
4. Pala, Rashtrakuta and Gurjara-Pratihara