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: Biochemistry
[{'content': 'What is the pH of blood under normal physiological conditions? \nSelect and explain. \nA. 6.8, B. 7.1, C. 7.4, D. 7.9', 'role': 'user'}, {'content': 'Answer: C \nExplanation: The pH of aerial blood is normally close to 7.40, with a normal range considered to be about 7.35 to 7.45. An aerial pH less than 7.35 is considered acidemia; an aerial pH greater than 7.45 is considered alkalemia. Under pathologic conditions the extremes of aerial blood pH have been noted to range as high as 7.8 and as low as 6.9. Ref: Levitzky M.G. (2013). Chapter 8. Acid-Base Balance. In M.G. Levitzky (Ed), Pulmonary Physiology, 8e.', 'role': 'assistant'}]