Final answer:
Option 2). The sensory neurons of the knee extensor muscles are inhibited following a tap of a physician's reflex hammer just below the knee cap.
Step-by-step explanation:
The correct answer is 2) sensory neurons of the knee extensor muscles.
The doctor's reflex hammer stimulates the sensory neurons of the knee extensor muscles by tapping right below the knee cap. This causes the knee reflex, an involuntary response, to begin. The motor neurons in the knee extensor muscles receive signals from the sensory neurons and pass them along to the spinal cord, which in turn causes the muscles to contract and kick the leg. The quadriceps muscle, the patella, and the patellar tendon comprise the major extensor anatomy of the knee, arranged from proximal to distal. The rectus femoris, vastus lateralis, vastus intermedius, and vastus medialis are muscles that make up the quadriceps muscular group.