Even though this question is missing the excerpt, it is still answerable.
Answer:
The situation irony in "The Tell-Tale Heart" shows:
A. The narrator's frantic insistence that he is sane only helps to convince readers that he is not.
Step-by-step explanation:
"The Tell-Tale Heart" is a short story by Edgar Allan Poe. The narrator's insistence concerning his sanity is excessive and, for that very reason, not believable. He ends up confessing to having killed an old man. His motives were the man's eyes and heart. He saw the man's vulture-like blue eye as en evil eye. He also believed he could hear the man's heart beating. There is nothing to prove the narrator is not insane, but he still tries to convince the reader by revealing how logical and premeditated his crime was - which, again, is even more proof of how mentally disturbed he is.