## **Core Concept**
The Neonatal Mortality Rate (NMR) is a critical indicator of newborn health and is defined as the number of deaths of newborns under 28 days of age per 1000 live births. It reflects the quality of prenatal care, delivery services, and postnatal care.

## **Why the Correct Answer is Right**
To calculate the Neonatal Mortality Rate (NMR), we first need to determine the number of live births and the number of neonatal deaths. Given:
- Total births = 4050
- Still births = 50
- Therefore, live births = Total births - Still births = 4050 - 50 = 4000
- Infant deaths within 7 days = 50
- Infant deaths within 28 days = 150

The NMR specifically refers to deaths within the first 28 days of life per 1000 live births. So, the number of neonatal deaths is 150.

## **Why Each Wrong Option is Incorrect**
- **Option A:** Without calculation, we cannot assume this is correct.
- **Option B:** Similarly, this option requires verification through calculation.
- **Option D:** This option also needs to be checked against our calculations.

## **Clinical Pearl / High-Yield Fact**
A key point to remember is that the NMR is an important indicator of the quality of healthcare in a region, especially regarding prenatal, delivery, and newborn care. A high NMR suggests areas for improvement in these services.

## **Correct Answer Line**
To calculate NMR: (Number of deaths under 28 days of life / Number of live births) * 1000 = (150 / 4000) * 1000 = 37.5

**Correct Answer: B. 37.5**