Who was Ajitnath Tirthankara in his previous life?

Answer: Option B

The soul that became Bhagavan Ajitnath, in its earlier incarnation, was the great king Vimalvahan of Susima city in Mahavideh area. He purified his soul to a level where he could earn the Tirthankar-nam-and-gotra-karma. When king Jitshatru became old and wanted to devote the last part his life to spiritual pursuit.