Which of the following functions is associated with motor nerves?

The function associated with motor nerves is controlling muscle movement. Motor nerves are part of the peripheral nervous system and are responsible for transmitting signals from the central nervous system to the muscles. This transmission allows for voluntary and involuntary movements of the body. When a motor nerve is stimulated, it triggers the muscle fibers to contract, resulting in movement.

In contrast, instigating sensory response, relaying pain signals, and processing sensory information are functions typically linked to sensory nerves. Sensory nerves transmit information from sensory receptors to the central nervous system, allowing for the perception of stimuli such as touch, pain, temperature, and other sensations. Thus, the distinct function of motor nerves focuses specifically on directing muscle actions, making "controlling muscle movement" the correct choice in this context.