This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Pharmacodynamics, Subject name: Pharmacology
[{'content': 'Ratio of median lethal dose to median effective dose is called? \nSelect and explain. \nA. Drug potency, B. Therapeutic index, C. Potentiation, D. Therapeutic efficacy', 'role': 'user'}, {'content': 'Answer: B \nExplanation: Therapeutic Index (T.I.): T.I. = LD50 /ED50 It is a measure of the safety of a drug. It is calculated as a ratio of LD50 to ED50. Drugs having high T.I. are safer whereas those having low T.I. are more likely to be toxic.', 'role': 'assistant'}]