The poetic device used by Edgar Allan Poe in the sentence "there was an iciness, a sinking, a sickening of the heart" is called consonance.
This device is marked by the repetition of identical or similar consonant sounds, in this case, "s" in neighbouring words that have different vowel sounds.
Your answer my friend will be option c, [Consonance], need help with anything else please ask !!!!, i am right here to help.
