The correct answer is Vajji.Mahajanapadas:?There were a total of 16 Mahajanapadas i.e. there were 16 major kingdoms in ancient India.Mahajanapadas were in existence from 600 B.C to 345 B.C.Most of the Mahajanapadas had a capital city and were covered by huge walls made up of wood, bricks or stones.In that era, Aryans were the most important tribes and were known as Janas.These kingdoms were near the Indo-Gangetic plain and that's why major agricultural reforms were noticed in that era.The names of 16 Mahajanapadas are:KasiKosalaAngaMagadhaVajjiMallaChedi/ChetiVatsaKuruPanchalaMatsyaSurasena/ShurasenaAssakaAvantiGandharaKambojaVajji and Malla were Gana-Sanghas.The Gana-Sanghas had a government by the assembly and within the assembly, they had an oligarchy.