Its either A or C. thats all i can say though but B and D you can rule out. I hope i helped a little
It will rain next. The moist air has lots of gas water. And when the warm gas water meets the cool temperature in the atmosphere, it will become liquid water. And when liquid water becomes more and more, it will form rain.
Relative humidity. A psychrometer has two thermometers, one for dry-bulb temperature and the other wet-bulb temperature.
