This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: General anatomy, Subject name: Anatomy
[{'content': 'H zone contains \nSelect and explain. \nA. Only myosin, B. Actin and myosin, C. Alfa actinin, D. None', 'role': 'user'}, {'content': 'Answer: A \nExplanation: H zone contains Only myosin M line passes from centre of H zone Ref:Guyton and Hall textbook of medical physiology 12th century edition,page number:86,87', 'role': 'assistant'}]