Which one of the following scholar, challenged Invincible Yajnavalkya for debate?

Gargi, as one of the disputants in the debate, questioned Yajnavalkya on his claim of superiority among the scholars. She held repeated arguments with him. Gargi and Yajnavalkyas exchange centered on the ultimate warp of reality (warp means the basic foundation or material of a structure or entity). Her initial dialogue with Yajnavalkya tended to be too metaphysical, such as unending status of the soul, away from practical situations. She then changed her approach and asked him pointed questions related to the environment existing in the world, the question of the very origin of all existence.