Answer:
C. Both Arabs and Kurds are mostly followers of Sunni Islam.
Explanation:
Around 90% of Arabs, and 98% of Kurds, are followers of Sunni Islam. An explanation for this is that the regions where these two ethnic groups live were conquered by Sunni muslims over a thousand years ago, while Shi'a Islam was mostly confined to Persia (Iran) where very few Arabs and Kurds live.