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': 'Common precursor of mineralocoicoid, glucocoicoids and sex steroids ? \nSelect and explain. \nA. Pregnenolone, B. a-hydroxyprogesterone, C. Dehydrotestosterone, D. Deoxycoisol', 'role': 'user'}, {'content': "Answer: A \nExplanation: Ans. is 'a' i.e., Pregnenolone", 'role': 'assistant'}]