What constant temperature does water freeze at, measured in Kelvin?

Water freezes at a temperature of 0 degrees Celsius, which corresponds to 273.15 Kelvin when converted to the Kelvin scale. In scientific contexts, it is common to approximate this as 273K for simplicity. The freezing point of water is a fundamental physical property and is used as a reference point in various scientific calculations, including those involving changes in state.

The other temperatures provided correspond to other physical phenomena: 373K is the boiling point of water at standard atmospheric pressure, 100K is much lower and would not correspond to common phases of water, and 0K represents absolute zero, the theoretical temperature where all molecular motion ceases. Thus, the correct answer of 273K highlights the freezing point of water in the Kelvin scale.