The best example of stage directions is Loud, sharp knocks on the door.
What is a stage direction?
This is an instruction in the text of a play indicating the movement, position, or tone of an actor, or the sound effects and lighting.
The Loud, sharp knocks on the door is the directions for what should happen on stage.
Options B and C are dialogues whikle the option D is introducing a character.
Therefore, the correct answer is option A.
Read more about stage directions here:
https://brainly.com/question/404162