Answer: I believe the correct answer is Alliteration.
Explanation: "Nothing besides remains. Round the decay Of that colossal wreck, boundless and bare The lone and level sands stretch far away."
There are several occurrences of the same letter or sounds throughout the 2 sentences. Such as, "Round and remains, boundless and bare, lone and level, and sands and stretch.
Which means it is Alliteration, not personification.
I hope this helps everyone out!