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
A autosomal recessive disorder caused by mutation in SLC19A2 gene and characterized by megaloblastic anemia, diabetes mellitus and sensorineural hearing loss. This child responds to which nutrient 
Select and explain. 
A. Vitamin B12, B. Vitamin c, C. Vitamin B1, D. Folic acid
C: Vitamin B1
Answer: C: Vitamin B1 
Explanation: This is Thiamine Responsive Megaloblastic syndrome:

It occurs due to mutation of SLC19A2 gene, encoding thiamine transporter protein, Leading to abnormal thiamine transportation.

Clinical features:

Megaloblastic anemia
Diabetes mellitus
Sensorineural hearing loss.