Question

what are the purposes of a prologue in a play?
to provide information about the inner thoughts and feelings of a character
to set the mood and tone of the play and provide background information
to provide information about how the stage should be set and what props are needed
to give some insight into the relationships among different characters
to provide a hint to the audience about what will happen later in the play

Answer 1

to give some insight into the relationships among different characters.

Answer 2

The main function of a prologue tells some earlier story and connects it to the main story. Similarly, it is serves as a means to introduce characters of a story and throws light on their roles. In its modern sense, a prologue acts as a separate entity and is not considered part of the current story that a writer ventures to tell.

Thus the answer is to set the mood and tone of the play and provide background information