I'm pretty sure I got this question on my PPL theory exam. I too was torn between the two options, as both were reasonably valid but incomplete answers. I picked one, and don't remember whether I got it marked right or not. There was another dodgy question about what is the most likely personal defect to render a pilot incapacitated. If I had read that question out in a game of Trivial Pursuit (tm) I'd have said, "Nup, crap question..." and chucked the card on the fire.
The point being, if this one question was on the knife edge of whether you passed or not then there were clearly plenty of other questions in the test that you were not properly prepared for. Learn your stuff and it wouldn't be a problem.
You failed the test, well rise above it and do it again.