Reply to specific ayah inside prayer, for both the imam and the followers, both the reciter and the one who is listening the recitation #2 The Messenger of Allah (ﷺ) told us to reply this ayah of Surah Rahman Fabi ayyi alaa-i rabbikumaa tukazzibaan. Meaning: So which of the favors of your Lord would you deny? by this - laa bishaayim min ni'amika rabbanaa nukazzibu falakal 'hamd Meaning: Ya Rabb! We don't disbelief any of your favour and all praise belongs only to you." It is to mentioned that, In the end of surah tin replying by saying “baala wa ana ‘ala dhalika minash shahidiin” and in the end of sura mursalat replying by saying “Amanna billah” and in the end of surah bakarah replying by saying “Amin” - these reports are weak narration.

Reference: Sahih (Albani). Abu Daud: 884