Skating on ice demonstrates that increasing pressure lowers the melting point of ice. When pressure is applied to ice, it causes a temporary phase transition, converting a thin layer of ice into liquid water, even at temperatures below the normal freezing point. This phenomenon reduces friction between the skate blades and the ice surface, enabling smoother skating movements. Hence, the correct answer is [C] decreases. Understanding this effect is essential in various fields, including sports science, materials engineering, and glaciology.