let us simplify the argument given -
SheilaSmoking tobacco for many years --> very likely to be harmful to smoker's health
TimGrandfather smoked 3 cigars a day from age 14 + lived up to 96 years --> Smoking has no effect at all
Immediately, we see a problem with Tim's reasoning. He tries to negate Sheila's conclusion by providing a single counterexample(there might be hundreds of thousands of people who might have suffered severe consequences to their health after smoking). Tim makes a extremely broad statement based on just one example.
Moreover, we are not told whether his uncle lived a healthy life or not; we are only told that his uncle lived a long life.
Let us look at the answer options --
Option A - Correct answerNote that Sheila says that smoking is "very likely" to cause cancer.
Option B - IncorrectWe do not know whether experts did NOT have access to information about Tim's grandfather.
Option C - IncorrectNowhere has it been mentioned that health experts have discounted his grandfather's case as an exception.
Option D - IncorrectTim does not assume. Rather, he assumes precisely the opposite -- that longevity and health are related (As in the case of his grandfather).
Option E - IncorrectNo. Tim does not make this assumption. Even if he did, it wouldn't be a weakness of his argument.
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