What does health mean?

Health is commonly understood as a state of complete physical, mental, and social well-being, not merely the absence of disease or infirmity. The definition encapsulated in the correct option emphasizes the idea that a healthy individual has all body systems functioning without any disease. This perspective acknowledges that true health involves more than just physical fitness or the absence of illness; it encompasses the overall effective functioning of the body.

When considering the other options, they refer to important aspects associated with health but do not encompass its full definition. Access to healthcare is a vital component that can facilitate better health outcomes, but it doesn't define health itself. Similarly, being physically fit relates to a specific aspect of health, focusing solely on physical wellness, and regular medical check-ups are preventive measures that can help maintain health but do not define what health is. Overall, the best definition of health includes the comprehensive functioning of all body systems without disease, which is why the second option is the correct answer.