Read this: Magadha (Sanskrit: मगध) formed one of the sixteen Mahā-Janapadas (Sanskrit: "Great Countries") or kingdoms in ancient India. The core of the kingdom was the area of Bihar south of the Ganges; its first capital was Rajagriha (modern Rajgir) then Pataliputra (modern Patna). Magadha expanded to include most of Bihar and Bengal with the conquest of Licchavi and Anga respectively, followed by much of eastern Uttar Pradesh and Orissa. The ancient kingdom of Magadha is heavily mentioned in Jain and Buddhist texts. It is also mentioned in the Ramayana, Mahabharata, Puranas. A state of Magadha, possibly a tribal kingdom, is recorded in Vedic texts much earlier in time than 600 BC. Magadha Empire had great rulers like Bimbisara and Ajatshatru.

Where was the center of Magadha?
What is the answer? (If it cannot be answered, return "unanswerable")
Bihar