A "plausible answer" refers to a response or explanation that seems reasonable and believable based on the information or evidence provided. Full definition
The only plausible answer to this question is that the cover letter failed to keep up with the changing times and has almost become outdated. (resumewriterforyou.com)
According to the limited research on breakup strategies, there are several plausible answers. (scienceofrelationships.com)
Update: I found it more difficult than usual to choose a correct answer to this question, particularly because there are two plausible answers which are the exact opposite of each other. (money.stackexchange.com)