Zero is the freezing temperature of water on which temperature scale?
The Celsius or Centigrade scale.
The Celsius scale has 0 for the freezing point and 100 for the boiling point of water.
Fahrenheit used different 0 and 100 points, so that 0 C =32 F and 100 C = 212 F. Degree steps are smaller than on the C scale.
The Kelvin scale uses the absolute zero for 0 K, which is about -273 C. The degree steps are the same as on the C scale, so that 273 K = 0 C.