Thanks for posting,
paulinoinny!
Let's break this
weaken question down from the top.
PREMISES
Snoring not common among smokers or non-smokers
Snoring more common among smokers.
CONCLUSION
Smoking by itself can induce snoring.
This is a classic causation/correlation mistake. We know A is correlated with B, and the author assumes A therefore must cause B. Classic rebuttals to this are:
1) reverse causation: B might cause A
2) third party: C might cause both A and B
3) coincidence!
(A) nails the target by introducing a third party, stress, that could be responsible for causing both snoring and smoking, which would handily explain the correlation.
Not the Problem
(B) This doesn't explain the connection to snoring.
(C) The conclusion was only that smoking could induce snoring, not that it was the only possible way to induce snoring. If most snorers don't smoke, then their snoring is caused by something other than smoking, but that's okay - it doesn't damage the conclusion.
(D) We were already told this in the premise!
(E) Who cares what smoking and snoring cause, we want to know what causes THEM!
Does that help clear things up a bit?