This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Environment and health, Subject name: Social & Preventive Medicine
For satisfactory vision the minimium illumination accepted is - 
Select and explain. 
A. 15 to 20 foot candles, B. 30 to 40 candles, C. 40 to 50 candles, D. 70 to 90 candles
A: 15 to 20 foot candles
Answer: A: 15 to 20 foot candles 
Explanation: An illumination of 15 to 20 foot-candles is accepted as a minimum basic requirement for satisfactory vision. 1 FC = 10.76 Lux Park's Textbook of Preventive and Social Medicine, 25th Edition, Pg 799