Step 1: Identifying the Rulers:
We must examine the historical identities of each ruler listed:
• Harihara (A) and Bukka (D): These two brothers founded the Vijayagara Empire in $1336 \text{ CE}$ and ruled as its first morchs under the Sangama Dysty.
• Rama Raya (B): A powerful general and prime minister who became the de facto ruler of the Vijayagara Empire during the $16^{\text{th}}$ century. He belonged to the Aravidu lineage and led the Vijayagara army in the catastrophic Battle of Talikota ($1565 \text{ CE}$).
• Rudradaman (C): He was a famous ruler of the Western Kshatrapas (Saka dysty) of the ancient period. He ruled over western India (Gujarat/Malwa region) during the $2^{\text{nd}}$ century CE ($c. 130$ -- $150 \text{ CE}$). He has no connection to the medieval southern Vijayagara Empire.
Step 2: Conclusion:
Since Harihara, Rama Raya, and Bukka are all major historical figures associated with the Vijayagara Empire, and Rudradaman is an ancient Saka ruler, Rudradaman is the odd one out. Hence, the correct option is (C).