Answer: Imagery, a rhyume sceme.
Explanation: these are the 2 i got and makw the most sense
An analysis of the poem as it gives your opinion
The last one has the correct punctuation and adverb
It is dark because Barnardo has trouble seeing the other guard.
This scene takes place at midnight and it is so dark Barnardo cannot see the other guard. Barnardo shows up for his shift, but he can't clearly make out who Francisco is. Francisco has the same problem because instead of answering Barnardo he tells him to identify himself first. They get it figured out and Barnardo begins his shift.