This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Lens, Subject name: Ophthalmology
[{'content': 'Most common cause of cataract is \nSelect and explain. \nA. Age related changes, B. Hereditary, C. Diabetes mellitus, D. Trauma induced', 'role': 'user'}, {'content': 'Answer: A \nExplanation: Most common cause of acquired cataract is senile cataract Refer: Khurana 6th edition page number 190', 'role': 'assistant'}]