Concept:The Battle of Badr was the first major military encounter between the Muslims and the Quraysh of Makkah.Explanation:The Battle of Badr took place in the month of Ramadan, in the second year after the Hijrah, which is the migration to Madinah.This event is recorded in Islamic history as the year 2 AH.Therefore, among the given options, the correct choice is the 2nd year AH.Answer:A. 2nd