If the options are metaphor, alliteration, allusion, and apostrophe, I believe the answer is metaphor, because the others don't fit.
Alliteration is the repetition of a consonant.
Allusion is reference to something or somebody outside of that literary work.
And apostrophe is the author speaking directly to somebody outside the poem, usually gods or a muse.
‘My cousin likes to exaggerate when he tells stories’ is the right answer
Upside and downside can mean a positive and a negative aspect of something, respectively. However, none of the options here present a couple of something negative and something positive: so I think we need to use the local meaning. So our analogy is:
on one extreme of some location (on the upper side): on the other extreme.
Therefore the best other couple is outside and inside: they also show two opposite locations.
