There are many things wrong with this quiz. I had 7 countries missing but only 3 were shown left of which I typed two definitely multiple times right. Croatia, Libya and Serbia e.g. are completely missing in the answers.
Agree with bennoelani – there are quite a few mistakes. If you're going to insist on a full spelling of Bosnia, please spell Herzegovina correctly – though allowing Bosnia (on its own) is common practice. Also UAE and CAR are standard abbreviations but they don't work here. The missing countries (Croatia, Libya etc) should certainly be added.