The correct answer is A. Never smoking
Step-by-step explanation:
The respiratory system is the system through which the body obtains oxygen from air while eliminating carbon dioxide, this is one of the most important systems because without oxygen organs cannot work. Due to this, we must avoid actions or behaviors that deteriorate this system, one of the main ways of doing this is by avoiding inhaling harmful substances because these deteriorate lungs and other structures in the respiratory system. This includes to never smoke or stop smoking because the toxins in cigarettes such as nicotine and carbon monoxide lead to serious diseases including lung cancer. Thus, the behavior that is the most beneficial for a healthy respiratory system is never smoking.