Which Surahs are called the Seven Deliverers (As-Sab' Al-Munjiyat)?

The entire Holy Quran is a healing, a guidance, and a mercy. There is no narration from the Prophet (peace be upon him) or his companions that seven specific surahs were named "Al-Munajjiyat" (the Deliverers). Eight surahs (Al-Kahf, As-Sajdah, Yaseen, Fussilat, Ad-Dukhan, Al-Waqi'ah, Al-Hashr, Al-Mulk) have appeared in a publication under the name "Al-Munajjiyat" without any basis for this appellation, despite the existence of authentic hadiths regarding the virtues of some of them, such as Surat Al-Mulk, which is reported to deliver one from the torment of the grave.