Who helps keep the audience informed of information with each scene?

Question

A. Actors

B. Narrator

C. Prologue

D. Writer

Answer 1

I would have to say the narrator. But not all movies have a narrator so in that case it is the writers job to keep the audiene informed with his dialogue

Answer 2

If it's the play it comes down to the writer, because the text has to have the information in it for the actors to interpret and share.  And there's only a narrator or a prologue if the writer writes one.