This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Male Reproductive System, Subject name: Physiology
[{'content': 'Which of the following hormones is mainly responsible for skeletal maturation? \nSelect and explain. \nA. Testosterone, B. Estrogen, C. Growth hormone, D. Insulin', 'role': 'user'}, {'content': 'Answer: A \nExplanation: Testosterone is a major factor responsible for the greater muscle mass and skeletal maturation. It has a myotrophic as well as androgenic (masculinization) action. Growth hormone increases skeletal and visceral growth. Insulin and thyroid hormones provide an additional stimulus for chondrocyte activity and growth of skeleton.', 'role': 'assistant'}]