Translation:Spain is hot, America is hotter, but Canada is the hottest.
Thanks for the comment, apologies for the system misleading you over this.
In Welsh there is only one way of saying the superlative, in this example Canada yw'r poetha
The literal translation is Canada is the hottest, which is correct in English.
However leaving out the definite article is also OK in English Canada is hottest
We set both answers as the best answer in English, Duolingo automatically generates its questions using the best answers that are set. Thus the two different answers you were given.
I've altered it to only show the answer with the definite article now.
Yes, the system generated a question without the definite article because that was one of the options we'd given it.
The situation now is that Canada is the hottest is the only phrase that will appear as a question, although someone typing the answer without the definite article while translating from Welsh will also be marked correct.
Obviously not generally, but heatwaves are possible as this report shows and so it's not impossible for this sentence to be factually accurate :- https://www.currentresults.com/Weather-Extremes/Canada/hottest.php