**Core Concept**
The Community Fluorosis Index (CFI) is a measure used to quantify the prevalence of dental fluorosis in a community, indicating the level of fluoride exposure in drinking water.

**Why the Correct Answer is Right**
The CFI is a widely used index that assesses the severity of dental fluorosis in a population, providing valuable information on the optimal fluoride concentration in drinking water. The index takes into account the number of people affected and the severity of the fluorosis. The correct answer is based on the work of a prominent researcher in the field of community water fluoridation.

**Why Each Wrong Option is Incorrect**
**Option A:** Not relevant to the topic, as this option does not mention a researcher or a study related to the Community Fluorosis Index.
**Option B:** Incorrect, as this option does not specify a researcher or a study related to the Community Fluorosis Index.
**Option C:** Incorrect, as this option does not accurately describe the researcher or study associated with the Community Fluorosis Index.

**Clinical Pearl / High-Yield Fact**
The Community Fluorosis Index is a useful tool for public health officials to monitor and adjust fluoride levels in drinking water to prevent excessive exposure, which can lead to dental fluorosis.

**Correct Answer: C. Dean. H. Trendley Dean.**