## **Core Concept**
The National Family Health Survey (NFHS) is a large-scale, multi-round survey conducted in a representative sample of households throughout India. It aims to provide reliable data on health and family welfare issues, which are crucial for policy formulation and program evaluation.

## **Why the Correct Answer is Right**
The correct answer, **D. International Institute of Population Sciences (IIPS)**, is the primary agency responsible for conducting the NFHS. The IIPS, located in Mumbai, India, has been the nodal agency for NFHS since its inception. The survey gathers data on various health and family welfare indicators, including fertility, mortality, family planning, and health care utilization. The IIPS works in collaboration with various stakeholders, including government agencies, NGOs, and international organizations, to ensure the survey's success.

## **Why Each Wrong Option is Incorrect**
- **Option A:** This option is incorrect because it does not specify a known agency or organization related to the conduction of NFHS.
- **Option B:** This option is incorrect as it does not accurately represent the primary organization responsible for NFHS.
- **Option C:** This option is incorrect because it does not correctly identify the main agency conducting NFHS.

## **Clinical Pearl / High-Yield Fact**
A key point to remember is that the NFHS provides critical data for health and family welfare programs in India. It is conducted in phases, with multiple rounds completed over the years, allowing for trend analysis and assessment of program impact.

## **Correct Answer:** D. International Institute of Population Sciences (IIPS).