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: Radiology
[{'content': 'Gas reaches colonic end in a newborn by? \nSelect and explain. \nA. 2-3 hours, B. 4-5 hours, C. 6-7 hours, D. 8-10 hours', 'role': 'user'}, {'content': 'Answer: D \nExplanation: 8-10 hours REF: Basic anatomical and physiological data for use in radiological protection by Jack Valentin, ICRP Page 128 Colonic transit time of different age group is Newborn 1 year 5-15 years Adults Male Female 8 hours 10 hours 11 hours 12 hours 16 hours', 'role': 'assistant'}]