## Core Concept
Primary health care (PHC) is an essential health care approach that is based on practical, scientifically sound, and socially acceptable methods and technology made universally accessible to individuals and families in the community through their full participation and at a cost that the community and country can afford. It is the first level of contact between the individual and the national health system, bringing health care as close as possible to where people live and work.

## Why the Correct Answer is Right
The correct answer emphasizes the comprehensive and equitable nature of primary health care, focusing on accessibility, affordability, and community participation. It encompasses health promotion, disease prevention, diagnosis, treatment, and rehabilitation, addressing the major health problems and needs of the community.

## Why Each Wrong Option is Incorrect
- **Option A:** Without the specific details of option A, we cannot directly address its accuracy in relation to primary health care principles. However, if it aligns with the core principles of PHC such as accessibility, community participation, and comprehensive care, it would not be incorrect.
- **Option B:** Similarly, without specifics, we can't directly refute option B. If it contradicts fundamental PHC principles, it would be considered incorrect.
- **Option D:** Assuming option D aligns with PHC principles, its incorrect labeling as the exception would stem from a misunderstanding or misrepresentation of PHC.

## Clinical Pearl / High-Yield Fact
A key point to remember is that primary health care is not just about providing health services but also about addressing the social determinants of health. It involves **equity**, **accessibility**, and **community participation**, making it a cornerstone of a well-functioning health system.

## Correct Answer: D.