This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Lower limb, Subject name: Anatomy
A patient experiences paralysis of the muscle arising at the femur and contributes directly to the stability of knee. Which of the following muscle is involved ? 
Select and explain. 
A. Semimembranosus, B. Vastus lateralis, C. Saorius, D. Biceps femoris
B: Vastus lateralis
Answer: B: Vastus lateralis 
Explanation: All the muscles given contributes to the stability of the knee joint Only vastus lateralis arise from the femur remaining arise from the hip joint. Ref: Gray's Anatomy The Anatomical Basics of Clinical Practice 41 e pg 1362.