**Core Concept**
The Net Reproduction Rate (NRR) is a demographic measure that assesses the average number of daughters a woman would have in her lifetime, taking into account mortality rates, fertility rates, and other factors that influence population growth. It is a crucial indicator of population dynamics and reproductive health.

**Why the Correct Answer is Right**
The correct answer, **C. Number of girl babies born to a woman and taking into account only alive once**, accurately reflects the NRR's focus on the number of daughters a woman would have in her lifetime, accounting for mortality rates. This measure helps policymakers and researchers understand the potential for population growth or decline, as well as the impact of various health interventions on reproductive outcomes. The NRR is calculated by multiplying the number of daughters born to a woman by the probability of survival of those daughters to reproductive age.

**Why Each Wrong Option is Incorrect**
**Option A:** The number of girl babies born to a woman does not account for mortality rates, making it an incomplete measure of reproductive potential. The NRR must consider the probability of survival to accurately estimate population growth.
**Option B:** The number of babies born to a woman includes both sons and daughters, but the NRR specifically focuses on the number of daughters, as they are the ones who would go on to reproduce.

**Clinical Pearl / High-Yield Fact**
The NRR is an essential tool for understanding population dynamics and reproductive health. A high NRR indicates a population that is likely to grow, while a low NRR suggests a declining population. Policymakers can use this information to inform decisions about family planning, healthcare, and economic development.

**✓ Correct Answer: C. Number of girl babies born to a woman and taking into account only alive once**