The accurate statement about ethnic groups in Southwest Asia is:
Arabs are the largest ethnic group in the region.
This statement reflects the demographic reality of Southwest Asia, where Arabs constitute a significant portion of the population across many countries in the region. The other statements are inaccurate as Arabs are not the majority in every country, Kurds are not the largest ethnic group on the Arabian Peninsula (they are primarily located in areas of Iraq, Turkey, Syria, and Iran), and people in the same ethnic group may follow different religions.