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: Surgery
[{'content': 'Following genetic counseling in a family for Familial polyposis coli for a 15 year old person, APC gene mutation is present. Next step of screening is \nSelect and explain. \nA. colonoscopy from now, B. Colonoscopy from 10 years before the detection of Ca. In family, C. Occult blood in stools every year till 30 years., D. CECT + colonoscopy', 'role': 'user'}, {'content': 'Answer: A \nExplanation: If APC gene mutation is present colonoscopy done from 10 years of age.', 'role': 'assistant'}]