The correct answer is option 3, Charaka. Charaka was the court physician of Kanishka. Charaka was a renowned physician in ancient India and is considered one of the principal contributors to the field of Ayurveda, the traditional Indian system of medicine. His work, the Charaka Samhita, is a comprehensive text that covers various aspects of medicine, including diagnostics, treatments, and the theory of health and disease. Charaka`s expertise and contributions to medicine earned him recognition as the court physician during the reign of Kanishka, who was a prominent ruler of the Kushan Empire in the 2nd century CE. As the court physician, Charaka would have played a significant role in providing medical care and advice to Kanishka and his court.