Final answer:
Without the context of the specific plot twist, it is difficult to determine the correct type of irony with certainty. However, situational irony typically describes scenarios where there is a surprising discrepancy between expectations and reality in a plot twist.
Step-by-step explanation:
The type of irony that best describes a plot twist depends on the specific details of the scenario. Verbal irony occurs when what is said is the opposite of what is meant. Situational irony happens when there is a discrepancy between what is expected to happen and what actually occurs. Dramatic irony is when the audience or reader knows more about a situation than the characters do, creating a contrast between the character's understanding and the actual situation. Sarcasm is a form of verbal irony that is usually intended to mock or convey contempt.
Since there isn't an exact plot twist provided in the question, a general understanding is that if the expectations of a character or the reader are subverted by the actual outcome in a surprising or humorous way, it's likely a case of situational irony. However, without the context of the specific plot twist, it is difficult to determine the correct type with certainty.