Read this excerpt from The Miracle Worker.

(The lights begin to come up, down left, on a long table and chair. The table contains equipment for teaching the blind by touch – a small replica of the human skeleton, stuffed animals, models of flowers and plants, piles of books.)

Which element of drama does the author use in this excerpt?

dialogue with background information
stage directions that set the scene
stage directions that reveal emotion
dialogue with information about blindness