During the heating of ice from −10∘C to steam at 120∘C under a constant rate of heat supply, in which one of the following stages will the temperature of the substance remain unchanged despite continuous input of heat?
a) Heating steam from 100∘C to 120∘C
b) Warming ice from −10∘C to 0∘C
c) Melting of ice at 0∘C
d) Heating water from 0∘C to 100∘C