The Schwann cell is

The correct option is D Associated with myelinated and non-myelinated nerve fibre
There are two types of Schwann cells, myelinating and non-myelinated. Myelinating Schwann cells wrap around axons of motor and sensory neurons to form the myelin sheath. Schwann cells are involved in many important aspects of peripheral nerve, conduction of nervous impulses along axons, nerve development and regeneration, trophic support for neurons, production of the nerve extracellular matrix, modulation of neuromuscular synaptic activity and presentation of antigens to T-lymphocytes.