A Difficulty in Developing Gene Therapy for Diseases of the Nervous

A difficulty in developing gene therapy for diseases of the nervous system is that

A) neurons are located throughout the body.
B) correcting a defect in a neuron anywhere in the body would also affect the brain, in unpredictable ways.
C) nerve cells (neurons) do not divide, and so the change would not be perpetuated.
D) the nervous system has many functions.
E) nervous tissues comprise half of the body's mass.