•Sciatica occurs due to pressure on the sciatic nerve which is a spinal nerve. Pain radiates from the sciatic nerve and runs down from the lower back to the legs and hips.
•Diabetes occur due to deficiency of the hormone Insulin in the body which causes rise in blood sugar level.
•Parkinson's disease is associated with the deficiency of dopamine. It is caused due to the loss of brain cells that produce dopamine and is a degenerative disorder of central nervous system. It affects the motor system. Symptoms include aging, slow movement, rigidity and stiffness of muscles causing tremors or trembling which is involuntary shaking movement of muscles.
•Multiple sclerosis is a disease associated with the brain and spinal cord. The immune system destroys the protective covering of the nerves.
So, the correct answer is C.