**Core Concept:** Preventive and social medicine refers to the integration of preventive healthcare, public health, and community medicine into the curriculum of medical schools. It emphasizes the importance of addressing social determinants of health and promoting health equity.

**Why the Correct Answer is Right:** The correct answer is the **World Health Organization (WHO)**. The World Health Assembly (WHA) is the decision-making body of the World Health Organization, and it recommended the inclusion of preventive and social medicine in the medical curriculum in 1970. This recommendation aimed to equip doctors with knowledge and skills necessary to address the health needs of communities and promote overall public health.

**Why Each Wrong Option is Incorrect:**
A. The **Indian Council of Medical Research (ICMR)** is a research organization focused on medical research in India, not the curriculum development of medical schools.
B. The **National Health Service (NHS)** is a healthcare system in the United Kingdom, not directly related to curriculum development for Indian medical schools.
C. The **Indian Medical Council (IMC)** is the regulatory body overseeing medical education in India, not directly involved in curriculum development.
D. The **Indian Medical Association (IMA)** is a professional organization for doctors in India, not responsible for curriculum development.

**Clinical Pearl / High-Yield Fact:** In 1997, the National Board of Examinations (NBE) in India introduced the concept of "comprehensive curriculum" for medical education, which incorporated preventive and social medicine into the undergraduate medical curriculum. This highlights the importance of this field in modern medical education and its recognition by relevant authorities like NBE.