2.1 The Truth Condition

True. I'm assuming that "modern audience" means an audience informed by the consensus of mainstream scientific opinion. You can find people today who still think the earth is motionless at the center of the universe, but these don't qualify as a "modern audience" in this sense.

The explanation for the given correct answer is that the persuasive power of an argument is determined by how believable or plausible its premises are to a specific audience, rather than whether the premises are actually true. In other words, an argument can be persuasive even if its premises are not objectively true, as long as they are perceived as plausible by the audience being targeted. This highlights the importance of understanding and appealing to the beliefs and values of the intended audience when trying to make a persuasive argument.

False. The premises may be false, but an audience may still have good reason to believe them, given the evidence available. And if so, then they may function as premises of a good argument, in the sense that the premises give the audience good reasons to accept the conclusion.

No. Plausibility may vary from audience to audience, but the actual truth or falsity of a claim like this one does not. Whether cell phone usage is a leading cause of brain cancer is true or false independent of what anyone happens to believe about it. If it's true, it's true for everyone, and if it's false, it's false for everyone.