Final answer:
The correct option that requires the most energy is melting 1 kg of ice, which involves a phase change that requires a significant amount of energy.
Step-by-step explanation:
The correct option that requires the most energy is d. Melting 1 kg of ice. This is because melting ice involves a phase change, which requires a significant amount of energy compared to temperature changes. The amount of energy needed to melt 1 kilogram of ice is 334 kJ, which is equivalent to the amount of energy needed to raise the temperature of 1 kg of liquid water from 0°C to 79.8°C. The energy required for vaporization is even greater, as it would take 2256 kJ to change 1 kg of liquid water at the boiling point to steam.