Here are the answers:
1. D. Humidity can be measured using g/m3, while relative humidity is measured as a percentage.
2. D. The relativehumidity is 100%, so condensation occurs.
3. B. The temperature fell overnight, and colder air can hold less water vapor.
4. D. No, as this would mean that the air holds more water vapor than it can.
Hope this helps, I took the quick check so these are 100% correct I garentee it.
Bye y'all, have a nice day.