The correct definition of situational irony is that it is a contrast between a character's expectations and the actual outcome of their actions or situation, often leading to an unexpected twist. It plays on the expectations that readers or the audience are likely to bring to a work.
From the options provided, none perfectly match this definition. However, the first option comes closest, though it inaccurately emphasizes the character's expectations rather than the contrast with the actual situation.
To summarize, situational irony involves an unexpected outcome that contrasts with what was anticipated.