Permissibility of offering Sunnah Qabliyyah in the Masjid

Q 1: Is it permissible to perform Sunnah Qabliyyah (supererogatory Prayer performed before an obligatory Prayer), such as that of Fajr (Dawn) Prayer at home? And if I do so then hear the Iqamah (call to start the Prayer) being called, should I interrupt the prayer or complete it? A: it is preferable to perform Al-Sunan Al-Rawatib (supererogatory acts that were stressed and regularly performed by the Prophet) and other Nafilah (supererogatory) prayers at home, based on what is reported in Sahih Muslim in a long Hadith wherein the Prophet's (peace be upon him) said, "You must perform (optional) prayers in your houses, for the best prayer performed by a person is that performed at home, except the obligatory prayer." Nevertheless, if you fear missing the congregational prayer as a result of offering Sunnah Qabliyyah at home due to the short period remaining before Iqamah, then you should offer it in the Masjid (mosque). Accordingly, if you are performing Sunnah Ratibah then the Iqamah is called, you must interrupt the supererogatory prayer and make it up after the obligatory Prayer, or after sunrise regarding Fajr Prayer. This is in compliance with what the Prophet (peace be upon him) said, "When the prayer commences then there is no prayer (valid), (Part No. 6; Page No. 124

A: it is preferable to perform Al-Sunan Al-Rawatib (supererogatory acts that were stressed and regularly performed by the Prophet) and other Nafilah (supererogatory) prayers at home, based on what is reported in Sahih Muslim in a long Hadith wherein the Prophet's (peace be upon him) said, "You must perform (optional) prayers in your houses, for the best prayer performed by a person is that performed at home, except the obligatory prayer." Nevertheless, if you fear missing the congregational prayer as a result of offering Sunnah Qabliyyah at home due to the short period remaining before Iqamah, then you should offer it in the Masjid (mosque). Accordingly, if you are performing Sunnah Ratibah then the Iqamah is called, you must interrupt the supererogatory prayer and make it up after the obligatory Prayer, or after sunrise regarding Fajr Prayer. This is in compliance with what the Prophet (peace be upon him) said, "When the prayer commences then there is no prayer (valid), (Part No. 6; Page No. 124) but the obligatory prayer." (Related by Imam Ahmad in his Musnad, and Imam Muslim in his Sahih Book of Hadith) It is also related by Al-Tirmidhy, Ibn Majah, Abu Dawud and Al-Nasa'y. However, if the obligatory prayer commences while you are in the second Ruku` (bowing) of the supererogatory prayer, then it is permissible to complete it reciting shortly and you need not interrupt it.May Allah grant us success. May peace and blessings be upon our Prophet Muhammad, his family, and Companions.