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
What is the recommended illumination for general office work? 
Select and explain. 
A. 100 lux, B. 400 lux, C. 900 lux, D. 1000 lux
B: 400 lux
Answer: B: 400 lux 
Explanation: The recommended illumination for casual reading is 100 lux, 400 lux for office work, 900 lux for fine assembly and for watch making 2000 - 3000 lux is recommended. Ref: Park's Textbook of Preventive Medicine, 17th Edition, Page 519.