Correct Option: C
The convocation of an assembly at Kannauj was one of the most significant events of the reign of Harsha. The purpose of this assembly was to simplify the doctrines of Mahayanism. This assembly was convened in 643 A.D. It was attended by kings of eighteen countries, 3000 Brahmanas and Jains, 3000 Buddhist monks of Mahayana and Hinayana sects and 1000 Buddhist monks of Nalanda Vihara. The famous Chinese traveler, Hiuen Tsang was also present and presided the assembly.