B. To enable the reader to visualize the ferocity of Santiago's foe.
Explanation:
In Ernest Hemingway's "The Old Man And The Sea", the endurance and experience of the old fisherman was in direct contrast with his victim, the marlin that he had caught. The experienced old man battled with the fish in his attempt to keep it under control but later lost almost all except the bones to the sharks.
Hemingway provided detailed description of the shark attacking Santiago's marlin. The shark was a <em>"fish built to feed on all the fishes in the sea, that were so fast and strong and well armed that they had no other enemy"</em>. Santiago also admitted the shark "<em>had no fear at all and would do exactly what he wished"</em>. The detailed description of the shark enables the reader to visualize the shark's ferocity against the old man's experience yet old age.
