Well, you're probably right there... the ones who didn't notice the high angle of attack are probably dead. When looking at quizzes like this, I try to think of the best answer that a non-pilot could take away for some future unintended emergency, so if they only knew of one cause for a stall, which correction of such cause would be most likely to save their lives? Just think about your basic stall training... what is the first action you take toward recovery, increasing power or reducing the angle of attack? If the typical lay person associates speed with the power setting or throttle and climb or descent with attitude or elevator control, as I suspect they do, if they remembered your quiz answer the first thing they would be doing to recover is add power rather than drop the nose, which in a small single-engine aircraft would likely throw them into a spin. On the other hand if they are taught that a stall occurs "when the nose is too high" and to reduce back pressure or push the stick forward, not only is it a corrective action that does not assume power is available, but is also more likely to enable our hapless pilot to have a chance to live through the next few minutes of unscheduled basic flight training as well.