Atmospheric conditions are well-governed by humidity. Which one among

Atmospheric conditions are well-governed by humidity. Which one among the following may best define humidity?

Form of suspended water droplets caused by condensation
Deposition of atmospheric moisture
Almost microscopically small drops of water condensed from and suspended in air
The moisture content of the atmosphere at a particular time and place
This question was previously asked in
UPSC CDS-1 – 2019
The correct answer is D. Humidity is a term used to describe the amount of water vapor present in the atmosphere. It is a measure of the moisture content of the air at a specific time and location. Humidity can be expressed in various ways, such as absolute humidity (mass of water vapor per unit volume or mass of air) or relative humidity (ratio of actual water vapor content to the maximum possible water vapor content at a given temperature and pressure).
Humidity is defined as the moisture content of the atmosphere.
Options A and C describe phenomena like fog or clouds, which are results of condensation when the air becomes saturated with water vapor (i.e., reaches 100% relative humidity). Option B describes deposition processes like dew or frost. None of these directly define humidity itself, which is the presence of water vapor in the air.