'Gajapati' (Lord of Elephants) was the name of a very powerful ruling dynasty of :

Orissa

The correct answer is Option (3) → Orissa

As per the tradition of Vijaynagara, Gajapati literally means Lord of elephants. This was the name of a ruling lineage that was very powerful in Orissa in the fifteenth century. In the popular traditions of Vijayanagara the Deccan Sultans are termed Ashvapati or lord of horses and the Rayas are called Narapatis or the lord of men.