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: Anatomy
Which of the following is locking muscle for knee ? 
Select and explain. 
A. Popliteus, B. Hamstring, C. Quadriceps, D. None
C: Quadriceps
Answer: C: Quadriceps 
Explanation: Ans. is 'c' i.e., Quadriceps Locking muscle --Quadriceps femoris (especially vastus medialis pa).Unlocking muscle --Politeus.