**Core Concept**
The question is referring to a method of vital statistics collection, which is essential for understanding epidemiological trends, disease patterns, and healthcare planning. This method involves a dual approach to ensure accuracy and completeness of birth and death data.

**Why the Correct Answer is Right**
The correct answer is based on the "Dual Record System" or "Dual Reporting System", where two independent methods are used to collect vital statistics. One method involves continuous enumeration by an enumerator, who is responsible for recording births and deaths on a regular basis. The other method involves an independent survey by an investigator supervisor, who verifies the data collected by the enumerator. This dual approach helps to identify discrepancies and ensure the accuracy of the data.

**Why Each Wrong Option is Incorrect**
* **Option A:** This option is incorrect because the "Single Record System" relies on a single method of data collection, which may lead to inaccuracies and underreporting.
* **Option B:** This option is incorrect because the "Chain-Ladder Method" is used for estimating mortality rates, but it does not involve continuous enumeration and independent survey.
* **Option C:** This option is incorrect because "Vital Statistics" is a broader term that refers to the collection and analysis of data on births, deaths, and other vital events, but it does not specifically describe the dual record system.

**Clinical Pearl / High-Yield Fact**
The dual record system is a crucial aspect of public health surveillance, as it helps to identify trends, patterns, and anomalies in vital statistics, which can inform healthcare policy and planning.

**Correct Answer:** D.