Problem: A nurse is counseling a client who is trying to quit smoking. The client complains about feeling irritable and restless since stopping cigarettes. What is the MOST likely explanation for these withdrawal symptoms? A. Nicotine is a stimulant, so the client should feel more energetic. B. The client's lungs are healing and adjusting to the lack of smoke inhalation. C. Nicotine has psychoactive properties, and the client's body is reacting to its absence. D. The client's body is eliminating toxins from cigarette use.