Saudi Arabia founded the Gulf Cooperation Council (GCC) in 1981 along with the UAE, Kuwait, Qatar and Bahrain. Which sixth country completed this founding list?

The correct answer is Oman. The Gulf Cooperation Council was formally established in May 1981 in Riyadh by six Gulf Arab monarchies acting together: Saudi Arabia, the United Arab Emirates, Kuwait, Qatar, Bahrain and Oman. The organisation's founding charter set out goals of coordinating economic, security, cultural and social policy among these six sovereign, oil-rich Gulf states, all of which share monarchical systems of governance and geographic proximity around the Arabian/Persian Gulf. Oman completes the list correctly because its ruling Sultanate signed the founding charter alongside the other five states, making it an original member rather than a later addition. Yemen is incorrect, and this is the single most important distractor in this question, because although Yemen occupies the southern part of the Arabian Peninsula and borders Saudi Arabia and Oman directly, it has never been admitted as a GCC member; Yemen's republican political system and historically separate development as North and South Yemen set it apart from the six monarchies that founded and still compose the GCC. Iraq is incorrect because, despite being a major Gulf-adjacent oil producer and an OPEC founding member, it was never part of the GCC's founding or subsequent membership, largely due to its republican government and regional political tensions in the early 1980s. Jordan is incorrect because, although Jordan is an Arab monarchy, it does not border the Gulf and was never invited to join the GCC's founding group, which was designed specifically for the six Gulf-facing Arabian Peninsula monarchies. The recurring exam confusion is assuming any prominent Arabian Peninsula or Gulf-adjacent state must be a GCC member; the reliable takeaway is to fix the six names firmly, Saudi Arabia, UAE, Kuwait, Qatar, Bahrain and Oman, and note explicitly that Yemen has never held membership.