Which of the following dynasty was not the part of "tripartite struggle", which fought for centuries to control over one particularly prized area Kannauj?

Correct option is A

Kadamba was not the part of "tripartite struggle".
 For centuries, rulers belonging to the Gurjara-Pratihara, Rashtrakuta and Pala dynasties fought for control over Kanauj.
 The Tripartite Struggle for Kanauj had happened between The Palas of Bengal, The Pratiharas of Central India, The Rashtrakutas of Deccan. 
 ​​The struggle lasted for 200 years and weakened all of them which enabled the Turks to overthrow them. 
 Thus, it is clear that Pala, Rashtrakuta and Gurjara-Pratihara dynasties fought the 'Tripartite struggle'.