This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: General physiology, Subject name: Physiology
The clearance of drug means 
Select and explain. 
A. Volume of plasma which is cleared of drug in unit of time, B. Amount of drug excreted in urine, C. Amount of drug metabolized in unit of time, D. All of the above
A: Volume of plasma which is cleared of drug in unit of time
Answer: A: Volume of plasma which is cleared of drug in unit of time 
Explanation: Clearance of a substance is the volume of plasma cleared of the substance in unit time ie in one minute. (REF: TEXTBOOK OF MEDICAL PHYSIOLOGY GEETHA N 2 EDITION, PAGE NO - 353)