Instructions Full Game: These are multiple-choice quizzes with four possible answer choices that include all questions in a given set.     
Identify the following organization:

An intergovernmental organization of 13 nations, founded on September 14, 1960 in Baghdad by the first five members (Iran, Iraq, Kuwait, Saudi Arabia, and Venezuela), and headquartered since 1965 in Vienna, Austria.
Guardian Angels
Big Brothers Big Sisters of America
OPEC
Illuminati