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: Pediatrics
Which of the following substance is toxic to neurons – 
Select and explain. 
A. Unconjugated bilirubin, B. Bile salt, C. Haemoglobin, D. Melanin
A: Unconjugated bilirubin
Answer: A: Unconjugated bilirubin 
Explanation: None