A prologue is a term that is used to provide readers additional details that progress the story plot. It is largely utilized by authors for several reasons, such as providing setting information about the story.
Hence, considering the available options, the purpose a prologue served are:
>. to provide details that may be important to the text
>. to offer an opinion or perspective about the text as a whole
>. to discuss important events that caused the author to write the text
