This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: General pharmacology, Subject name: Pharmacology
TherapeutIc index is a measure of: 
Select and explain. 
A. Safety, B. Potency, C. Efficacy, D. Selectivity
A: Safety
Answer: A: Safety 
Explanation: The gap between the therapeutic effect DRC (Dose Response Curve)and the adverse effect DRC defines the safety margin or the therapeutic index of a drug. So it is a measure of safety Therapeutic index =median lethal dose /median effective dose or LD 50 /ED 50 Ref; KD Tripathi Pharmacology 7th edition (page no;56 )