In a motor reflex, such as the patellar tendon reflex, afferent action back to the spinal cord is mediated through which of the following?

a. Interneurons

b. Sensory neurons

c. Motor neurons

d. Sympathetic chain ganglia

The correct answer will be option-B.

Explanation:

The patellar tendon reflex is the kicking movement of the lower leg in response to the tap on patellar cap used to test the L2, L3, and L4 segments of the spinal cord in the body.

The spinal cord interacts with muscles through muscle sensors called muscle spindle which signals after the stretching of the muscle. The signals are sent to the spinal cord through afferent neurons or sensory neurons which starts the reflex action to prevent overstretching of the muscle.

Thus, Option-B is the correct answer.