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': 'All of the following are Bile acids except \nSelect and explain. \nA. Lithocholic acid, B. Taurocholic acid, C. Deoxycholic acid, D. Chenodeoxycholic acid', 'role': 'user'}, {'content': 'Answer: B \nExplanation: The two principal (primary) bile acids formed in the liver are cholic acid and chenodeoxycholic acid. In the colon, bacteria conve cholic acid to deoxycholic acid and chenodeoxycholic acid to lithocholic acid. In addition, small quantities of ursodeoxycholic acid are formed from chenodeoxycholic acid. Ursodeoxycholic acid is a tautomer of chenodeoxycholic acid at the 7-positionRef: Ganong&;s review of medical physiology 23rd edition Page no: 438', 'role': 'assistant'}]