Should read the question carefully and take a break if you chose C... this is a pure fatigue trap

E ruled out a possibility of reversed cause, hence strengthening the argument. All the other answer choices were somewhat irrelevant to the conclusion of the argument (how snoring and abnormality had a correlation).

Did this question by diagramming and hunted directly for the answer i was looking for, didn't even read the rest of the answer choices. Might actually be a potentially good method, as some of those answer choices are really misleading. I only noticed how B was misleading after I submitted my answer. Got 29 seconds under!