متى نزلت أول آية؟

The first verses of the Quran were revealed to Prophet Muhammad (peace be upon him) on ليلة القدر (Laylat al-Qadr, the Night of Decree), which falls within the month of Ramadan. This is confirmed by the Quran itself in Surah Al-Qadr (97:1): إنا أنزلناه في ليلة القدر ("Indeed, We sent it down on the Night of Decree"). The angel Jibrīl (Gabriel) appeared to the Prophet in the Cave of Hira and conveyed the opening verses of Surah Al-Alaq: اقرأ باسم ربك الذي خلق ("Read in the name of your Lord who created").

The correct answer is ليلة القدر. This night is described in the Quran as being better than a thousand months (Surah Al-Qadr 97:3), and it is traditionally observed during the last ten nights of Ramadan, most commonly on the 27th night.

The other options are incorrect. بعد الهجرة (after the Hijra) is wrong because the revelation began approximately 13 years before the migration to Madinah. ربيع الأول 12 (12th of Rabi al-Awwal) is associated with the Prophet's birth, not the first revelation. رمضان 13 names the month correctly but gives an arbitrary date and is not the established term used in Islamic tradition for the event of the first revelation.