Final answer:
The World Health Organization's definition of health is physical, mental, and social well-being, not just the absence of disease or infirmity.
Step-by-step explanation:
The World Health Organization's definition of health is option c: Physical, mental, and social well-being, not just the absence of disease or infirmity. According to the WHO, health is not merely the absence of illness, but rather a state of complete physical, mental, and social well-being. This definition emphasizes that health encompasses various aspects of a person's overall well-being, including their physical, mental, and social functioning.