This is the second worst pub quiz question that I have come across. There are so many "curves with single bends that go to infinity" that the question is meaningless.
BTW, the worst question was this: "Which continent is wider in the South than in the North?" You might like to ponder that for a microsecond.
The official answer from the book was, if you can believe it, Antarctica. I was flabbergasted (and said so). Some years later, I stumbled upon the key to this idiocy, quite by accident, while browsing my Encyclopaedia Britannica (as you do). An article on the continents said, quite reasonably (I am paraphrasing here): "With the exception of Antarctica, all continents are wider in the North than in the South." The question setter obviously read this exact same sentence and thought that a question could be forged out of it.