When someone says on a shadowy something far away where the river widens to meet the bay a line of black that bends and floats on the rising tide like a bridge of boats kind of figurative language is used

answer: "the beating heart symbolizes the narrator's conscience, or his sense of guilt and wrongdoing" so its b

explanation:

"to look at him, or hear him describe it, he had no guilt. however, poe decided to symbolize this man's subconscious guilt through the heartbeat."