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
Rett'\s syndrome occurs due to deficiency of – 
Select and explain. 
A. Niacin, B. Biotin, C. Carotene, D. Vitamin D
B: Biotin
Answer: B: Biotin 
Explanation: None