This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: None, Subject name: Social & Preventive Medicine
Psychrometer is used to measure – 
Select and explain. 
A. Humidity, B. Air velocity, C. Room temperature, D. Radiant temperature
A: Humidity
Answer: A: Humidity 
Explanation: Humidity is measured by

Dry and wet Bulb hygrometer
Sling psychrometer
Assmann psychrometer