This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Disorders of Amino acid Metabolism, Subject name: Pediatrics
A child with subluxation of lens and mental retardation died. Which of the following would have helped in his treatment? 
Select and explain. 
A. Biotin, B. Pyridoxine, C. Zinc, D. Riboflavin
B: Pyridoxine
Answer: B: Pyridoxine 
Explanation: Subluxation of lens and mental retardation in a child who died suggests underlying homocystinuria Pyridoxine (vitamin B6) is useful in its treatment