An unknown substance is heated from 10 °C to 25 °C. The table below shows the state of the substance at different temperatures. Time (minutes) Temperature of liquid (degrees Celsius) State of matter 0 10 Solid 2 15 Solid 4 17 6 17 8 17 10 23 Liquid 12 25 Liquid Which statement is correct about the unknown substance? Its melting point is 17 °C. Its melting point is 15 °C. The substance sublimes at 15 °C. The substance exists as a gas at 17 °C.