During the process of vaporization of a liquid, its temperature remains constant.
The correct option is A
As a liquid is heated, it's temperature increases. As its temperature increases, the molecules of the liquid gain energy and their kinetic energy increases. As the kinetic energy increases, the molecular motion increases and the molecules of the liquid overcome the force of attraction between them. On continuous heating, a particular temperature is reached where the molecules of the liquid leave the surface in the form of vapour. This produces a pressure above the liquid which is equal to the atmospheric pressure and the liquid starts boiling. At this stage, the temperature of the liquid remains stationary even on further heating.