**Core Concept**
Primary health care (PHC) is a holistic approach to healthcare that focuses on preventing and treating diseases, promoting health, and addressing the social determinants of health. It involves a collaborative effort between the community, healthcare providers, and other stakeholders to deliver accessible, equitable, and effective healthcare services.

**Why the Correct Answer is Right**
The correct answer, "Decentralised approach," is not a core principle of primary health care. While decentralization is an important aspect of healthcare administration, it is not explicitly mentioned in the Alma-Ata Declaration or the World Health Organization's (WHO) definition of PHC. The WHO emphasizes the importance of community participation, intersectoral coordination, and the use of appropriate technology in PHC.

**Why Each Wrong Option is Incorrect**
**Option A:** Intersectoral coordination is a key principle of PHC, as it involves collaboration between different sectors, such as healthcare, education, and social services, to address the social determinants of health.

**Option B:** Community participation is a fundamental principle of PHC, as it empowers communities to take ownership of their health and well-being, and to participate in decision-making processes.

**Option C:** Appropriate technology refers to the use of technology that is accessible, affordable, and effective in addressing the healthcare needs of communities. This is a principle of PHC, as it aims to provide healthcare services that are tailored to the needs of the community.

**Clinical Pearl / High-Yield Fact**
The Alma-Ata Declaration, adopted in 1978, is a landmark document that emphasizes the importance of primary health care in achieving health for all. It highlights the need for community participation, intersectoral coordination, and the use of appropriate technology in PHC.

**Correct Answer Line**
✓ Correct Answer: D. Decentralised approach