Answer
The heating curve of that process is represented by the drawing:
- The segment represented by "b" corresponds to the freezing of the ice, that occurs at: Temperature = 0$^{\circ}$ C.
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Work Step by Step
You can use the figure on the bottom of the page 81 as the basis to draw the cooling curve.
Since the melting/freezing point of water is at 0$^{\circ}$, the liquid water will release energy and freeze at that temperature.