9. the is the temperature to which air must be cooled at constant pressure to reach saturation.

Is the temperature to which air must be cooled at constant pressure to reach saturation?Saturation is the point at which the air holds as much water vapor as it possibly can.) The is the temperature to which air must be cooled at constant pressure to reach saturation. Until this temperature is reached, condensation cannot occur and rain cannot fall.

The answer is option a.

Sorry  i don't understand can you rephrase that