The answer is C: reasoning that doesn't make sense when you examine it.
A logical fallacy is a flaw in an argumentative process whereby a conclusion is reached based on premises that do not attain to logical rules and that do not stand the test of careful examination. Aristotle analyzed some of the most common fallacies which are to be avoided, and, in broad terms (since their categorization is more complicated and their ramifications more profound than the space here would allow to elaborate upon), they can be categorized as fallacies that are intentionally deceptive or fallacies that are product of ignorance or carelessness.