I think this was more of an issue with guessing, just based on the way it was worded, what with having three similar answers that deal with the countries being dictatorships
Also, it wasn't really brought up how the question also mentions France and Australia, adding some confusion
The article also treats these results as though no American eighth-graders know what Canada is, even though 66% didn't think Canada was a dictatorship
Finally, Canada seems to just not be mentioned much in history classes. In my
textbook, Canada is focused on three times (according to the index): Once when describing its oil reserves, lumped in with mostly the rest of North America, when describing the changes in the nation following WWII, and once when describing the changes in the nation following the Berlin Wall being brought down.
I'm thinking that the results on the test were caused mostly by a severe lack of under-representation of Canada in our history classes, not by the students simply being ignorant of Canada as a whole.