Correct option is A
The king who renounced the world and followed Acharya Bhadrabahu to a place in Karnataka, according to Jain tradition, was Chandragupta Maurya.
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Acharya Bhadrabahu was the last of the Jain Shruta Kevalis (one who has complete knowledge of the Jain scriptures).
During a severe twelve-year famine in Magadha (around the 3rd or 4th century BCE), Acharya Bhadrabahu led a large group of Jain monks, including his royal disciple Chandragupta Maurya, to South India.
The place in Karnataka where this migration settled is identified as Shravanabelagola.
Jain tradition holds that Chandragupta Maurya abdicated his throne, became a Jain monk under Bhadrabahu, and performed Sallekhana (fasting unto death) at Shravanabelagola. The spot is sometimes referred to as Chandragiri Hill after him.