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
Recommended reflection factors include each of the following, except - 
Select and explain. 
A. Ceilings 80%, B. Roofs 40%, C. Walls 50 to 60%, D. Furnitures 30 to 40%
B: Roofs 40%
Answer: B: Roofs 40% 
Explanation: (PARK TB 23rd edtn pg 740) Recommended reflection factors include:- - ceilings and roofs - 80% - walls - 50 to 60% - furniture - 30 to 40% - floor not more than 15 to 20%