Which logical fallacy is used in the text?
Victor is not qualified to run the Environmental Club. Have you seen his sister's huge, horrifically inefficient car? The planet cries whenever she turns on the ignition.
guilt by association: a negative association intended to discredit someone or something slippery slope fallacy: the false assumption that a small first step will lead to extreme consequences false dichotomy: an argument that presents only two choices when more options exist
A strong argument uses valid reasoning and logic in support of a claim. When an argument or claim introduces irrelevant information or misrepresents the issues at hand, it may be committing a logical fallacy. Logical fallacies can hurt a writer's credibility and can lead readers to draw false conclusions.
A logical fallacy may present irrelevant information:
Fallacy | Description
ad hominem | an attack against the person making the argument, rather than the argument itself
appeal to nature | an argument that assumes the natural choice is always the best choice
bandwagon fallacy | an argument that assumes the popular choice is always the best choice
circular reasoning | an argument that supports a claim with the claim itself
guilt by association | an unfair negative association with another person or group that is intended to discredit someone or something
A logical fallacy may misrepresent the issues at hand:
Fallacy | Description
false causation | the assumption that because two things happened together, one caused the other
false dichotomy | an argument that presents only two choices when more options exist
hasty generalization | a broad claim based on too few observations
slippery slope fallacy | the false assumption that a small first step will necessarily lead to extreme consequences
straw man | a misrepresentation of an opponent's position that makes it easier to argue against

The text argues that Victor isn't qualified to run the Environmental Club because his sister drives a fuel inefficient car. However, the behavior of Victor's sister does not necessarily reflect Victor's own behavior. This illustrates a type of logical fallacy known as guilt by association.