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: 
Select and explain. 
A. ED50/LD50, B. LD50/ED50, C. ED50-LD50, D. ED50 XLD50
B: LD50/ED50
Answer: B: LD50/ED50 
Explanation: ref; KD Tripathi Pharmacology 7th edition (page no:55) 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. Therapeutic index =median lethal dose /median effective dose or LD 50 / ED 50