Final answer:
A double dash at the end of a line of dialogue typically indicates a pause in speech or an interrupted thought. It signifies a sudden break in the dialogue and is not used to denote a change in speaker or to punctuate questions or exclamations.
Step-by-step explanation:
A double dash at the end of a line of dialogue is typically used to indicate that the speaker has been interrupted or has trailed off abruptly, leaving the sentence unfinished.
This can signify a sudden change of thought, an interruption, or that the speaker has left the conversation hanging for dramatic or emotional effect. It's a way to show that the dialogue is incomplete or has been cut short without using an ellipsis, which usually indicates a longer pause or omitted text.
The correct usage of the double dash would align with the indication of a pause in speech or a sudden break in the dialogue, making it best associated with option 2 from the list provided by the student. However, it's important to note that it could potentially imply a continuation of dialogue, depending on the context within the narrative structure or character interaction.
It does not typically indicate a change in speaker, a question, or an exclamation, as these are represented differently through punctuation such as question marks, exclamation points, or paragraph breaks.