Final answer:
The line that contains a simile is C.
Step-by-step explanation:
The line that contains a simile is C. 'A phantom ship, with each mast and spar
Across the moon like a prison bar' uses the words 'like' to make a comparison between the ship and a prison bar, which is a simile. Similes compare two things using 'like' or 'as'. In this case, the moon is being compared to a prison bar.