Concept:Transformer losses are reduced by using good core materials and core construction methods.Explanation:A soft iron core is used because it easily magnetises and demagnetises, reducing hysteresis loss.Laminating the iron core reduces eddy current losses in the core.Designing an efficient iron core also helps to reduce flux leakage and energy waste.All these measures together ensure that energy losses in a transformer are kept to a minimum.Answer:Option C. I, II & III only.