It's not fair to put the EU in! After all Germany, Italy and France are part of the Union. Or at least give a sign or something, that there are not only countries in the quiz.
As an EU hater I agree with you. It is an international organisation heading towards a federal state and should it assume the status of a federal state it can then by considered in my mind a legitimate economy. However having double checked the 2012 G-20 summit website the EU is listed as one of the 20 major global economies. I will also make the quiz more clear in the instructions as you were unclear that the answers were not only nation states.