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: Orthopaedics
[{'content': 'An 18-yr-old boy was playing football when he suddenly twisted his knee on the ankle and he fell down. He got up after 10 minutes and again started playing, but the next day his knee was swollen and he could not move it. The most probable cause is - \nSelect and explain. \nA. Medial meniscus tear, B. Anterior cruciate ligament tear, C. Medical collateral ligament injury, D. Posterior cruciate ligament injury', 'role': 'user'}, {'content': 'Answer: A \nExplanation: This boy has : -\n\n\nHistory of twisting injury to the knee\nSwelling appearing next day.\n\n\nThis is classical to the medial meniscal injury.\nIn ACL injury swelling appears immediately due to hemarthrosis.', 'role': 'assistant'}]