The accurate statement about ethnic groups in Southwest Asia is:
c. Arabs make up the largest ethnic group in the region.
While there are many ethnic groups in Southwest Asia, including Kurds, Persians, and Turks, Arabs are indeed the largest ethnic group overall in the region. Options a, b, and d are not accurate for various reasons. For instance, Kurds are not the largest group on the Arabian Peninsula, not all countries have Arabs as a majority, and people within the same ethnic group may follow different religions.