This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Pharmacokinetics, Subject name: Pharmacology
What does the plasma concentration versus time graph indicates - 
Select and explain. 
A. Half life, B. Clearance, C. Elimination, D. Bioavailability
D: Bioavailability
Answer: D: Bioavailability 
Explanation: Ans. is 'd' i.e., Bioavailability o The extent of systemic bio availability is ordinarily calculated by relating the area under plasma concentrationtime curve after a single oral dose to that obtained after iv administration of the same amount (by which route a drug is 100% available).