This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: FMGE 2019, Subject name: Anatomy
Which muscle tendon is stretched in patellar tendon reflex? 
Select and explain. 
A. Biceps femoris, B. Quadriceps femoris, C. Adductor magnus, D. Quadratus
B: Quadriceps femoris
Answer: B: Quadriceps femoris 
Explanation: Quadriceps femoris stretches in patellar tendon reflex. Striking of the patellar tendon with a reflex hammer just below the patella stretches the muscle spindle in the quadriceps muscle.