Concept:Surah an-Nasr was revealed to announce the victory of Islam and the spread of its message.Explanation:The surah speaks about the help of Allah and the victory achieved for Islam.It refers to the conquest of Mecca, when Islam triumphed and people embraced it in large numbers.This victory showed that Islam was firmly established and had a bright future.Thus, the major teaching is the success and promising future of Islam.Answer:C. Islam has a bright future