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
OPV can be used if vaccine l monitor is showing? 
Select and explain. 
A. Colour of outer circle is same as inner square, B. Colour of outer circle is darker than inner square, C. Colour of outer circle is lighter than inner square, D. None of the above
B: Colour of outer circle is darker than inner square
Answer: B: Colour of outer circle is darker than inner square 
Explanation: Ans. is 'b' i.e., Colour of outer circle is darker than inner square