Who could replace Nitish Kumar as Bihar CM if he steps down?

Bihar CM Nitish Kumar filed his nomination papers for Rajya Sabha on Thursday after confirming that he would be stepping down from the CM post. It is being speculated that a BJP leader could replace Kumar as CM, with top contenders being Deputy Chief Minister Samrat Choudhary, Union Minister Nityanand Rai, and Bihar minister Dilip Kumar Jaiswal.