I think the right answer is B, I could be wrong (sorry if I am wrong)
Basically the subject is what it’s about, like say you were reading about art the subject of the passage is art
Answer:
He used figurative language because he used a simile to compare his feelings "I suppose I felt as one may imagine the unarmed mariner to feel when he is rescued by a friendly man-of-war from the pursuit of a pirate."
Explanation: