Which of the following excerpts from the short story “The Tell-Tale Heart” by Edgar Allan Poe best demonstrates the unreliability of the narrator?

A.
You should have seen how wisely I proceeded—with what caution—with what foresight—with what dissimulation I went to work!
B.
I heard many things in hell. How, then, am I mad? Hearken! and observe how healthily—how calmly I can tell you the whole story.
C.
And then, when I had made an opening sufficient for my head, I put in a dark lantern, all closed, closed, that no light shone out, and then I thrust in my head.
D.
Oh, you would have laughed to see how cunningly I thrust it in! I moved it slowly—very, very slowly, so that I might not disturb the old man's sleep.