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': 'Bilirubin secretion is stimulated by \nSelect and explain. \nA. Bile salts, B. Bile pigments, C. Secretin, D. CCK', 'role': 'user'}, {'content': 'Answer: A \nExplanation: Bile salts are the most important cholerectic or the substance that increases bile secretion. Cholecystokinin (CCK) is the most important cholagogue or substance that increases gallbladder contraction.', 'role': 'assistant'}]