The correct option is "D", " The Abbasid caliphate was not affected by conflicts within the Muslim community".
In fact there is no Muslim reign which was not affected by conflicts within the Muslim community after the martyrdom of the third Khalifa of Islam Uthman (ra). When he was attacked he made a prophecy that if today you kill me, the Muslims until the end of time will not be united, which to date is standing as witness.
