The healthiest option would be the cheese because cheese contains both healthy and non-healthy fats, the second best choice would be nuts, although they contain more protein than fat.
C. Submerge the fish under cold-running water. If you submerge the fish under hot water, the fish will start to cook; then when you actually start to cook it, some parts will be over cooked. Same thing with option B. The fish will start to cook. For option D, the fish will get old and take even longer to thaw.