**Core Concept**
The question is inquiring about a fertility indicator that estimates the average number of children a woman would have in her lifetime, reflecting her completed family size. This concept is crucial in understanding population dynamics and reproductive health.

**Why the Correct Answer is Right**
The correct answer to this question is Total Fertility Rate (TFR). TFR is a widely used fertility indicator that estimates the average number of children a woman would have in her lifetime based on the age-specific fertility rates of a population. It takes into account the fertility rates of all women in the reproductive age group (usually 15-49 years) and is expressed per 1,000 women. The TFR is a more accurate measure of completed family size compared to the General Fertility Rate (GFR), which only considers the fertility rates of women in the reproductive age group.

**Why Each Wrong Option is Incorrect**
* **Option A:** General Fertility Rate (GFR) is a fertility indicator that estimates the number of births per 1,000 women of reproductive age (usually 15-49 years) in a given year. While GFR is a useful measure, it does not account for the age structure of the population and therefore does not accurately estimate completed family size.
* **Option B:** Crude Birth Rate (CBR) is a measure of the number of live births per 1,000 people in a population, regardless of age or sex. CBR is not a fertility indicator and does not provide information on completed family size.
* **Option C:** Net Reproduction Rate (NRR) is a fertility indicator that estimates the number of daughters a woman would have in her lifetime, assuming a stable population with a constant age structure and fertility rates. While NRR is related to TFR, it only considers the number of daughters and does not provide an estimate of completed family size.

**Clinical Pearl / High-Yield Fact**
When analyzing fertility indicators, it's essential to consider the age structure of the population and the fertility rates of women across different age groups. TFR is a more accurate measure of completed family size compared to other fertility indicators, making it a crucial tool for understanding population dynamics and reproductive health.

**Correct Answer: D. Total Fertility Rate.**