M East country (4)
(Other definitions for iran that I've seen before include "Middle Eastern country" , "Country where the official language is Farsi" , "Country where ayatollahs replaced a shah" , "Modern-day Persia" , "Previously known as Persia" .)
(Other definitions for oman that I've seen before include "Middle Eastern country" , "Arabian peninsula country" , "Former Gulf country, Muscat and --" , "Sultanate, capital Muscat" , "Sultanate on the south-east coast of the Arabian Peninsula" .)
(Other definitions for yemen that I've seen before include "Enemy country in S Arabian peninsula" , "Country bordering Oman" , "Arabian republic, capital Sanaa" , "Republic on the Arabian Peninsula" , "Aden is found here" .)