The correct option is B Synthesising neurotransmitters for neurons.
Glial cells make up the bulk of nervous tissue and aid the neurons in their function. They help in the protection of the neurons against pathogens. They bring about insulation of the neurons by forming the myelin sheath. They also help in providing nourishment to the neurons by providing a close association between the blood vessels and the neurons. However, neurotransmitters are formed by the neurons themselves.