Answer:
D. neuritis.
Step-by-step explanation:
The suffix -itis which comes from Greek means inflammation. Since the root neuro refers to the nerves or nervous system, like the question said, it means that the combination of neuro and -itis in neuritis means an inflammation of the nerves.
Neurology is the study of nerves; nervous is the state of being anxious or worried; neuroism doesn't exist in English.