This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: G.I.T, Subject name: Physiology
[{'content': 'Normal intraabdominal pressure is \nSelect and explain. \nA. 0-8mmHg, B. 10-15mmHg, C. 15-20mmHg, D. 20-26mmHg', 'role': 'user'}, {'content': 'Answer: A \nExplanation: The abdomen behaves as a hydraulic system with a normal IAP of about 5-7 mmHg, and with higher baseline levels in morbidly obese patients of about 9-14 mmHg. Measuring IAP the bladder in the supine position is still the accepted standard method, but in patients in the semi-recumbent position (head of the bed elevated to 30 degrees and 45 degrees ), the IAP on average is 4 and 9 mmHg, respectively. Ref: guyton and hall textbook of medical physiology', 'role': 'assistant'}]