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
An 8 year old boy complaints of increasing muscle weakness. On examination, his calves are bulky and show muscle tightening. His serum creatine kinase levels are increasing with age. Which of the following is the most likely diagnosis? 
Select and explain. 
A. Hereditary sensorimotor neuropathy, B. Myelin deficiency, C. Dystrophin deficiency, D. Congenital myopathy
C: Dystrophin deficiency
Answer: C: Dystrophin deficiency 
Explanation: Answer- C. Dystrophin deficiencyMost likely diagnosis is duchenne Muscular Dystrophy due to Dystrophin deficiency.