What is occurring during the flat section of the graph below on the red arrow labeled boiling, between liquid and gas?    A. The temperature is no longer increasing even though heat is still being added because the heat is being absorbed to lower the melting point. B. Heat is being released, allowing particles of the liquid to overcome the pressure, and is why the temperature does not increase. C. Heat is being absorbed, allowing particles of the liquid to overcome the vapor pressure. D. Heat is being absorbed, allowing particles of the liquid to overcome the atmospheric pressure.