Making a claim that someone should not be trusted based on a past behavior unrelated to the claim at hand is called?

The correct answer is Ad Hominem, which refers to a type of fallacy where a claim is rejected or discredited based on an irrelevant characteristic or past behavior of the individual making the claim, rather than addressing the actual argument or issue. This tactic often shifts the focus away from the content of the argument itself and instead attacks the character or circumstances of the person presenting it, which can lead to unfair conclusions.

In the context of the question, making a claim about someone's trustworthiness based solely on unrelated past behavior exemplifies this fallacy. It fails to engage with the merits of the current claim and instead resorts to personal attacks, thereby undermining constructive dialogue.

The other options describe different logical fallacies. A Straw Man involves misrepresenting someone's argument to make it easier to attack, an Irrelevant Sample refers to drawing conclusions based on data from an unrepresentative population, and False Authority occurs when someone is cited as an expert in a field where they do not have relevant credentials. These are distinct from the concept of Ad Hominem, which specifically targets the individual rather than their argument.