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: Physiology
[{'content': 'The four major bile acids found in humans are synthesized from: \nSelect and explain. \nA. Cholesterol, B. Amino acids, C. Bilirubin, D. Protein', 'role': 'user'}, {'content': "Answer: A \nExplanation: When considering bile as a digestive secretion, it is the bile acids that represent the most impoant components. They are synthesized from cholesterol and secreted into the bile conjugated to glycine or taurine, a derivative of cysteine. Ref: Barrett K.E., Barman S.M., Boitano S., Brooks H.L. (2012). Chapter 25. Overview of Gastrointestinal Function & Regulation. In K.E. Barrett, S.M. Barman, S. Boitano, H.L. Brooks (Eds), Ganong's Review of Medical Physiology, 24e.", 'role': 'assistant'}]