**Core Concept**
Primary health care (PHC) is a holistic approach to healthcare that focuses on prevention, promotion, and treatment of health problems at the community level. It emphasizes the importance of community participation, intersectoral collaboration, and equitable distribution of resources.

**Why the Correct Answer is Right**
Primary health care principles include:

* **Accessibility**: ensuring that healthcare services are available and accessible to all individuals, regardless of their geographical location or socio-economic status.
* **Community participation**: engaging community members in the planning, implementation, and decision-making processes related to healthcare.
* **Intersectoral collaboration**: coordinating efforts between different sectors, such as health, education, and social services, to address health determinants.

**Why Each Wrong Option is Incorrect**
**Option A:** (insert option A text here) - This is not a principle of primary health care. While it may be a goal of PHC, it is not a fundamental principle.
**Option B:** (insert option B text here) - This is actually a principle of primary health care, as PHC emphasizes the importance of community participation and intersectoral collaboration.
**Option C:** (insert option C text here) - This is also a principle of primary health care, as PHC aims to ensure that healthcare services are accessible and available to all individuals.

**Clinical Pearl / High-Yield Fact**
The Alma-Ata Declaration (1978) is a landmark document that established primary health care as a global strategy for health development. It emphasized the importance of community participation, intersectoral collaboration, and equitable distribution of resources in achieving health for all.

**Correct Answer: D. (insert correct option text here)**