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
Richest source of vitamin I is - 
Select and explain. 
A. Milk, B. Egg, C. Green leafy vegetables, D. Fish oil
D: Fish oil
Answer: D: Fish oil 
Explanation: Ans. is 'd' i.e., Fish oil