ANS:B - increases but dew point remains constant.

During sensible cooling of air, its wet bulb temperature decreases but dew point remains constant. Sensible cooling refers to the process of cooling air without changing its moisture content. When air undergoes sensible cooling, its temperature decreases, causing its wet bulb temperature to decrease as well. This is because wet bulb temperature is a measure of the temperature reached by evaporative cooling of a wet surface in contact with the air. As the air temperature decreases, the cooling effect on the wet surface decreases, leading to a decrease in wet bulb temperature. However, the dew point temperature remains constant during sensible cooling because the moisture content of the air does not change. The dew point temperature represents the temperature at which the air becomes saturated with water vapor, leading to condensation. Sensible cooling does not alter the moisture content of the air, so the dew point temperature remains constant. Therefore, during sensible cooling of air, the wet bulb temperature decreases while the dew point temperature remains constant.