What term describes an argument that seems reasonable or probable?

The term that describes an argument or statement that appears reasonable or likely to be true is "plausible." In logical reasoning and critical thinking, plausibility refers to the quality of being believable or having a semblance of truth, even if not necessarily proven. When an argument is plausible, it presents a sense of credibility and is often based on sound reasoning or credible evidence, making it more convincing to an audience.

In contrast, the other terms do not fit this context. "Morose" relates to a gloomy or sullen disposition, which does not pertain to the concept of reasonableness in arguments. "Indifferent" describes a lack of interest or concern and does not convey any element of credibility or believability. "Eccentric" refers to something that is unconventional or deviates from the norm, which might not necessarily align with reasonableness or probability. Thus, "plausible" is the most fitting term for an argument that seems reasonable or probable.