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
Keshan card iomegaly - 
Select and explain. 
A. Se, B. Cu, C. Zn, D. Fe
A: Se
Answer: A: Se 
Explanation: Ans. is 'a' i.e., Se