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: Medicine
A-12-year old boy presents to the Outpatient department with a history of progressively increasing difficulty in walking and frequent falls. Physical Examination reveals an ataxic gait and nystagmus. All deep tendon reflexes were observed to be absent while the plantar response was 'Extensor'. What is the most likely diagnosis? 
Select and explain. 
A. Friedreich's Ataxia, B. Subacute Combined Degeneration of Cord (SACD), C. Becker's Muscular Dystrophy, D. Tabes Dorsalis
A: Friedreich's Ataxia
Answer: A: Friedreich's Ataxia 
Explanation: None