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: Physiology
[{'content': 'Group atrophy of muscle fibres denotes: \nSelect and explain. \nA. Enlarged motor units with all muscle fibres reduced dispropoionately, B. Enlarged motor units with all muscle fibres reduced to a same size, C. Reduced motor units with all muscle fibres reduced to a same size, D. Reduced motor units with all muscle fibres reduced dispropoionately', 'role': 'user'}, {'content': "Answer: B \nExplanation: Group atrophy denotes enlarged motor units where all the fibers in the group are reduced to the same size. This is typical of progressive denervation. Reduction in the size of muscle fibers with an accompanying enlargement of intact motor units (because of collateral reinnervation) and degenerative changes in some fibers are the main changes of denervation atrophy is called denervation atrophy. Ref: Ropper A.H., Samuels M.A. (2009). Chapter 45. Electrophysiologic and Laboratory Aids in the Diagnosis of Neuromuscular Disease. In A.H. Ropper, M.A. Samuels (Eds), Adams and Victor's Principles of Neurology, 9e.", 'role': 'assistant'}]