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
When ohotoludine reagent is added to water and if free chuirine is present, what colour will be produced? 
Select and explain. 
A. Pink, B. Yellow, C. Green, D. Red
B: Yellow
Answer: B: Yellow 
Explanation: Ans. is 'b' i.e., Yellow