The use of imagenology in literature, both prose and poetry, is a technique that has the purpose of communicating a message but through a visual experience and through imagination. Literally, in this passage, there is the mention of two images: the first, illumination, which brings forward the idea of visibility, and even more so, of underlining the importance of what is being shown. The second image is created by the description of the enormous and dangerous animals that swim inside and which represent both danger and fear. Through light and the idea of those dangerous animals, the author is trying to put forward the message of those fears that lurk inside and that might harm us. The correct answer then is C because light allows for colors to come through and it turns the shadows of fears (the twisting sharks) to be seen through the idea of hope.
Trivial details are details that have little to no relation to the evidence you are supporting. Supporting details back up you evidence strongly. Trivial details will often be used to keep the audience interested (ex: A fun fact about the moon.)
