Concept:The Battle of Badr is a key historical event in Islam, and the exact number of Muslim fighters is a standard exam fact.Explanation:The Muslim army under Prophet Muhammad (peace be upon him) at Badr consisted of 313 men.This number is often quoted as 313 or sometimes 314, but 313 is the most common figure in Islamic sources.The opposing Quraysh army was much larger, roughly 1000 men.Therefore, the correct option is the one that gives 313.Answer:313 (Option C).