All of these is your best answer.
Rhetoric of sentences: This occurs when you use a rhetorical device in a sentence, for example:
(Alliteration) He sleeps like a sloth.
Rhetoric of figures of speech: Uses other words to describe what is occurring, for example:
(Metaphors) The Mouth of a River.
(Simile) Jack is like a dog, he is loyal no matter what.
(Personification) The tree reminds me of Jack, they both stand tall and straight.
Rhetoric of sounds: Uses sound to convey meaning. For example, A long wail or moan can usually covey the meaning that the person is in pain. This can also be using Rhetorical Devices during speech.
Rhetoric of words: Uses words to convey meaning. This is using the rhetorical devices while writing.
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