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: Pharmacology
Therapeutic index is a measure of which of the parameters? 
Select and explain. 
A. Efficacy, B. Adverse effects, C. Safety, D. Potency
C: Safety
Answer: C: Safety 
Explanation: Therapeutic index is a measure of the margin of safety of a drug. Therapeutic index = Median lethal dose/Median effective dose. One estimate of a drug's margin of safety is the ratio LD50/ED50, the therapeutic index, which is a statement of how selective the drug is in producing it's desired versus its adverse effects.