The followers of the Islamic sect Sunnis supported Abu Bakr, who was the first caliph of Suni Islam. According to the belief of Suni Muslims, anyone capable and showing Islamic virtues can be a religious leader and a caliph, regardless of whether he is related to Muhammad or not, which was Shia Islam's claim. Quran is the Islamic sacred book, while jihad is the Islamic holy war.
The answer is: A.