The answer is A: Metaphor.
Explanation for each option:
A. Metaphor: This is the correct answer. A metaphor is a figure of speech that directly compares two different things by stating that one is the other. In the given text, "Love is a garden of flowers" is a metaphor because it compares love to a garden of flowers, suggesting that love has various aspects, some pleasant and some unpleasant, without using "like" or "as."
B. Rhyme: This is incorrect. Rhyme refers to the repetition of similar sounds, usually at the end of lines in poetry. The given text does not exhibit any rhyming words.
C. Tone: This is incorrect. Tone refers to the attitude or emotional quality conveyed by the writer or speaker. While the text does have a tone, the question specifically asks for the poetic device used, which is a metaphor.
D. Personification: This is incorrect. Personification is a figure of speech where human qualities are given to animals, objects, or ideas. The text does not attribute human characteristics to non-human entities; it simply compares love to a garden of flowers.