Oh come on! Congo. I know similar comments in other quizzes have addressed this, but following this logic I expect to see Australia on the 'o' version of this quiz. And if it isn't I'm going to spend my evenings writing long winded, incredulous, indignant comments on JetPunk until the cows come home....
While this makes sense, "Congo" is a shortened term that can colloquially refer to both DRC and Republic of the Congo. When being distinct and referring to them as two separate countries, the full names have to be used.