ANS:D - all 'a' , 'b' & 'c'

When the relative humidity of moist air is 100%, it means that the air is saturated with moisture, and the dew point temperature is equal to the wet bulb temperature. Therefore, the correct option is: all 'a', 'b', & 'c' Explanation:

• wet bulb temperature = dry bulb temperature: When the relative humidity is 100%, the air is saturated, and the wet bulb temperature, which represents the lowest temperature to which air can be cooled by evaporating water into it, becomes equal to the dry bulb temperature, which is the ambient temperature measured by a standard thermometer.
• wet bulb temperature = dew point temperature: Again, when the relative humidity is 100%, the air is saturated, and the wet bulb temperature and dew point temperature are equal.
• saturation temperature = dew point temperature: Saturation temperature refers to the temperature at which air becomes saturated with moisture. When the relative humidity is 100%, the air is saturated, and the dew point temperature is equal to the saturation temperature.