Final answer:
The reflex that causes muscle relaxation and lengthening in response to muscle contraction is known as the Golgi tendon reflex. So, correct answer is (A).
Step-by-step explanation:
A reflex that causes muscle relaxation and lengthening in response to muscle contraction is called a Golgi tendon reflex. This reflex functions as a safety mechanism to prevent muscle damage from excessive force during muscle contraction. The Golgi tendon organs, located at the junction between tendons and muscles, sense tension changes in the tendon when the muscle contracts.
If the tension is too high, the Golgi tendon organs send an afferent signal to the spinal cord to stimulate inter neurons, which then inhibit the motor neurons, causing relaxation of the muscle, preventing potential damage due to excessive contraction. This contrasts with the stretch reflex, such as the knee-jer-k reflex, which leads to muscle contraction in response to stretching.
This reflex occurs when the go-lg-i tendon organs, which are located in the tendons of muscles, detect tension or force on the muscle. When this happens, the go-lg-i tendon organs send signals to the spinal cord, which in turn sends inhibitory signals to the motor neurons responsible for contracting the muscle, causing it to relax and lengthen.