Hello. You did not present the text to which this question refers, which makes it impossible for this question to be answered accurately. However, I will try to help you in the best possible way.
The metaphor is a figure of speech that promotes a comparison between two elements. This comparison must be promoted implicitly or explicitly and has the function of creating a new meaning and promoting an intensification of this concept. This makes the text deeper and richer, promoting greater reflection on the topics covered.
Imagery is specific in the way that it helps to create a picture
I think a memo is a pronoun
The answer is D - explanation of nature