The white mater is composed of

a. fiber tracts

b. neuron cell bodies

c. sulci

d. gyri

e. b, c and d only

The correct answer is option A.

Explanation:

White matter is the component of CNS which consist neuron cell bodies or myelinated cell axons or nerve fiber collectively known as fiber tracts mainly. Glial cells also one of the component of white matter, made up of few sulci and gyri. White matter makes superficial regions of the spinal cord and deep parts of the cerebrum.

The neuron cell bodies of white matter sends signals to neurons and each other. White matter regulates the action potentials function as coordinators in between brain parts.

Thus, the correct answer is option A.