In "Things Fall Apart" the sentence that best explains the effect of using imagery in the passage is C. The author conveys a tragic tone with the images of fleeing fish and the blood-red lake.
By mentioning that even the sacred fish left the village and now the lake has turned red, the author clearly transmits the sense of tragedy left by the massacre: a lake, previously filled with sacred fish, now is tinted red from all the blood that poured into it from the villagers' death.