Evaporation is sometimes a cooling process always a cooling process always a warming process sometimes a warming process two of the above are correct.

Evaporation is always a cooling process. For evaporation to occur, energy is needed by the liquid molecules that are changing phase into gas. This energy is taken from the surroundings in the form of heat energy. So when evaporation occurs, the temperature of the surroundings will decrease, making evaporation a cooling process.