Concept:The question is about identifying the author of the famous Indian mathematical text Lilavati.Explanation:Lilavati was written by the great Indian mathematician and astronomer Bhaskaracharya (also known as Bhaskara II). It is the first part of his larger work Siddhanta Shiromani, composed in 1150 CE. The book covers topics like arithmetic, geometry, and algebra. The other options – Brahmagupta, Aryabhatta, and Ramanujan – were also renowned mathematicians, but they did not write Lilavati.Answer:Option C: Bhaskaracharya