Option c is the correct answer. A. Vishakhadatta is a Sanskrit playwright and poet who is known for his historical dramas, such as Mudrarakshasa and Devichandragupta. He lived in the 4 th or 5 th century CE and was a courtier of Chandragupta II. B. Varahamihira was an astronomer who lived in the 6th century CE. He was one of the nine jewels of the court of king Vikramaditya. He wrote several works on astronomy, astrology, and mathematics, such as Brihat Samhita, Brihat Jataka, and Panchasiddhantika. C. Charaka was a Sanskrit physician and scholar who lived in the 2 nd or 3 rd century BCE. He is considered as one of the founders of Ayurveda, the ancient Indian system of medicine. He wrote the Charaka Samhita, a comprehensive treatise on medicine, which is one of the two foundational texts of Ayurveda. D. Brahmagupta was a Sanskrit mathematician who lived in the 7 th century CE. He was the head of the astronomical observatory in Ujjain. He wrote several works on mathematics and astronomy, such as Brahmasphutasiddhanta and Khandakhadyaka. He is credited with giving rules for arithmetic operations with zero and negative numbers, as well as solving quadratic and indeterminate equations.