What facilitated the rapid spread of islam in the seventh and eighth centuries? the exhaustion of the byzantine empire after pyrrhic victories over the ostrogoths and vandals the capitulation of jewish and christian leaders direct military assistance from the sasanid state the unification of previously fractious and divided arab tribes?

The correct answer should be unification of previously fractious and divided Arab tribes

Many Arab countries were angry because the Byzantine empire tried to impose Christianity on them. They responded by joining together under the banner of Islam to spread and stop Christianity. This started in the 7th century and Muslims managed to win places like Persia, Syria, Egypt, and unite in order to push the Byzantines back.