Why Is a CNS Neuron Not Usually Replaced After It

Multiple Choice

Why is a CNS neuron not usually replaced after it is injured?

A) Most CNS neurons are not replaced because we have an abundance of neurons and it is not necessary to replace any that are injured.
B) Most CNS neurons are not replaced because the PNS neurons just take over the functions of any injured CNS neurons.
C) Most CNS neurons are not replaced because it is not possible to replace any injured cell in the body.
D) Most CNS neurons are not replaced because they contain Nissl bodies which prevents the cell from undergoing cellular division.
E) Most CNS neurons are not replaced because they lack centrioles so they cannot divide.