Your Friend Has a Paralyzed Arm

Your friend has a paralyzed arm. What physical events might have caused this?

A) damage to the part of the spinal cord that controls that arm
B) drug-induced failure at the neuromuscular junction
C) damage to the part of the brain that controls that arm
D) Any of these events could have caused the paralysis: damage to the part of the brain that controls that arm, damage to the part of the spinal cord that controls that arm, or drug-induced failure at the neuromuscular junction.