This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Endocrine System, Subject name: Physiology
[{'content': 'Which of the hormone has 4 subunits and 2 units for tyrosine kinase receptor binding? \nSelect and explain. \nA. Insulin, B. Glucagon, C. T3, D. ADH', 'role': 'user'}, {'content': "Answer: A \nExplanation: Insulin receptor is 'enzyme linked receptor Insulin binds to alpha-subunits => due to linkage, poions of b-subunits become auto-phosphorylated", 'role': 'assistant'}]