A couplet is a pair of lines in poetry that typically rhyme and have the same meter.
Based on the provided lines:
- A consists of two lines that do not rhyme.
- B consists of two lines that do not rhyme.
- C consists of two lines that do not rhyme.
- D consists of three lines; therefore, it cannot be a couplet.
Thus, none of the options provided are couplets in the traditional sense, as they do not form pairs of rhyming lines. However, the closest to a couplet based on overall structure is option C, as it has a similar length and thematic connection.
In conclusion, none of the options strictly fit the definition of a couplet. If choosing based on thematic pairing, C would be a potential choice, but it still doesn't fulfill the rhyming couplet criteria.