Answer:
C. irritated.
Step-by-step explanation:
In this excerpt of "The Tell-Tale Heart" Poe narrator is describing how he use to watch the old men sleeping, the narrator is shows how careful he was to don’t wake up the old man while he was opening the door of the bedroom to observe him, he is irritated because he is actually trying to convince the audience that he is a sane man and indeed he suffering from nervousness.