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: Unknown
[{'content': 'A five year old boy presents with precocious puberty and a blood pressure of 130/80 mmHg. Estimation of which of the following will help in diagnosis - \nSelect and explain. \nA. | 17 hydroxy-progesterone, B. | Cortisol, C. | Aldosterone, D. Renin', 'role': 'user'}, {'content': 'Answer: A \nExplanation: Ans- A. Ref- Nelson Textbook Of Pediatrics Vol. 1 20th ed Biochemical diagnostic studies show elevated levels of serum 17-OHP, the substrate for the defective 21-hydroxylase enzyme activity.', 'role': 'assistant'}]