Hello,
The answer is option C a metaphor that sustains the comparison for several lines, or for an entire poem.
Reason:
The answer is option C because extended metaphors are used in poems or any other type of writing that repeats the metaphor. Its not A because it is indeed a comparison but it does sometimes states it directly. Its not option B because metaphor are used but not in a daily use. Its also not D because there describing a simile.
If you need anymore help feel free to ask me!
Hope this helps!
~Nonportrit