The peripheral nervous system (PNS) consists of all the nerves and ganglia outside the brain and spinal cord. Therefore, the spinal cord and brain, which are part of the central nervous system (CNS), are not included in the PNS.
Among the options you provided, "sensors" (presumably referring to sensory receptors or sensory nerves) can be considered part of the peripheral nervous system.
Thus, the correct answer is sensors.