Final answer:
Florence Nightingale's theory of nursing can be demonstrated through the intervention of promoting good health and treating those who are ill in a holistic manner.
Step-by-step explanation:
Florence Nightingale's theory of nursing can be demonstrated through the intervention of B) Promoting good health and treating those who are ill in a holistic manner. Nightingale emphasized the importance of providing holistic care, considering the physical, emotional, and social well-being of patients. This approach involves addressing not only the illness but also the overall health of the individual.