The correct answer is A: 273 K for freezing water and 373 K for boiling water.
On the Kelvin temperature scale, water freezes at 273.15 K and boils at 373.15 K. This scale is an absolute temperature scale, starting at absolute zero (0 K), which is the theoretical point where all molecular motion ceases. The Kelvin scale is widely used in scientific contexts because it provides a direct measure of thermal energy.
Answer choice B is incorrect because it states 0 K for freezing water, which is absolute zero, not the freezing point of water. Similarly, choice C is incorrect as it lists 32 K for freezing water and 212 K for boiling water, which does not correspond to the correct temperatures on the Kelvin scale.