**Core Concept**
The **minimum number of newborns** required to calculate the percentage of **Low Birth Weight (LBW) babies** is crucial for epidemiological studies and public health planning. This concept is rooted in **biostatistics** and **epidemiology**, where sample size determination is essential for reliable estimates.

**Why the Correct Answer is Right**
To determine the percentage of LBW babies, a sufficiently large sample size is necessary to ensure the estimate is reliable and generalizable to the population. The correct answer is based on the principle that a certain minimum number of observations are required to achieve a desired level of precision in the estimate.

**Why Each Wrong Option is Incorrect**
**Option A:** This number is too small to provide a reliable estimate of the percentage of LBW babies in the population.
**Option B:** Similarly, this option does not provide enough observations to accurately estimate the prevalence of LBW.
**Option D:** This is also insufficient for making reliable estimates about the population.

**Clinical Pearl / High-Yield Fact**
Remember, for calculating percentages or proportions in a population, such as the percentage of LBW babies, the sample size must be sufficiently large to minimize sampling error and ensure the results are representative of the population.

**Correct Answer:** C. 300