To determine the melting point of ice, a thermometer is suspended in a beaker half filled with ice and kept at the room temperature. Which thermometer reading should be noted as the melting point of ice?

• A. The temperature when all the ice taken melts and water remains.
• B. The temperature when the ice just starts to melt.
• C. When the mercury level in the thermometer remains constant at a particular temperature.
• D. When the temperature just begins to increase from -2°C.