A good question. I'll admit that I am surprised at the high number of incorrect answers; I would have expected 70 to 80 percent to get this right.
I'm not surprised that the wrong answers are fairly evenly divided over the wrond answers; they are all very good distractors. Well done!
And Andrew, thank you for providing the links and explanation that really explain the results; they are a good addition to the explanation and references given bij Yousaf.