Correct Answer: (b) Ujjain
Note: The ancient name of Ujjain was Avantika., According to the Buddist texts, the Anguttara Nikaya, Avanti was one of the Salasa Mahajanapadas (sixteen great realms) of the 6th century BCE. Avanti was divided into Northern Avanti with Ujjaiyini as it's capital and Southern Avanti with Mahishmati as it's capital.