What caused Islam to spread throughout Arabia?

Islam spread through Arabia as Muhammad’s followers carried its message beyond Mecca and Medina, including to other towns and cities. This outreach helped new communities learn about and adopt the faith, making D, “Followers of Islam promoted their message while traveling to other cities,” the best answer. The Hijrah was Muhammad’s migration from Mecca to Medina, not a journey through which people across Arabia generally joined Islam.

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