The correct answer is option-3: water at 273 K has more energy than ice at the same temperature. This statement is consistent with the understanding of the energy states of water and ice at this temperature.

At 273 K (0 degrees Celsius), both water and ice exist in the solid phase. However, the energy content of each substance is different. Water molecules in the solid state possess more energy than ice molecules at the same temperature. This is due to the strong intermolecular forces within the ice lattice structure, which restricts the motion of water molecules and lowers their energy content.

Because water at 273 K has more energy than ice at the same temperature, it is less effective in cooling. When attempting to cool a system using water at this temperature, the higher energy content of the water molecules makes it more difficult for them to absorb heat from the system and lower its temperature. On the other hand, ice at the same temperature has a lower energy content and can efficiently absorb heat from the system, resulting in more effective cooling.

Therefore, option-3 correctly explains why water at 273 K is less effective in cooling compared to ice at the same temperature.