Answer:
This is an infinitive.
Explanation:
A gerund is a verb used as a noun; "suggesting" is not used as a noun in this case.
The correct answer is "I heard many things in hell. How, then, am I mad? Hearten! And observe how healthily-how calmly I can tell you the whole story."
Explanation: The narrator of "The Tell-Tale Heart" is unreliable because in this excerpt he claims to hear something that is supernatural, and states that the proof is in his narration. His tone is nervous and shows that he is panicking while attempting to convince the reader that he is calm, and not crazy.
C. He mentions knives to describe how the cold wind feels.
Out of all of these, I would say this answer provides the most detailed descriptions/sensory details. It also makes use of metaphors to give more depth.
Hope this helps :)