Answer: B. The river of boiling blood represents the blood that the sinners spilled in life.
Step-by-step explanation: Symbolism is the use of symbols to signify ideas and qualities, by giving them symbolic meanings that are different from their literal sense, generally, making it much deeper and more significant. In the given excerpt from Canto XII of Dante's Inferno, he uses symbolism in the line "Where we approach a river of blood boiling" the river of boiling blood represents the blood that the sinners spilled in life (the blood of the neighbors harmed by violence).