**Core Concept**
The assessment of obesity involves various measurement indices that help in evaluating the body mass index (BMI) and body fat percentage. These indices are used to determine the severity of obesity and to monitor its progression over time. Quetelet's index, Broca index, and Corpulence index are commonly used measures to assess obesity.

**Why the Correct Answer is Right**
Sullivan's index is not a widely recognized or used measure for assessing obesity. The other options, Quetelet's index, Broca index, and Corpulence index, are all valid measures of obesity. Quetelet's index, also known as the body mass index (BMI), is calculated by dividing the weight in kilograms by the square of the height in meters. Broca index is a more accurate measure of body fat percentage, taking into account the individual's height and weight. Corpulence index is another measure that assesses the severity of obesity. In contrast, Sullivan's index is not a standard or widely accepted measure for assessing obesity.

**Why Each Wrong Option is Incorrect**
**Option A:** Quetelet's index is a widely used measure for assessing obesity, calculated by dividing the weight in kilograms by the square of the height in meters.
**Option B:** Broca index is a valid measure of body fat percentage, taking into account the individual's height and weight.
**Option D:** Corpulence index is another measure that assesses the severity of obesity.

**Clinical Pearl / High-Yield Fact**
When assessing obesity, it's essential to use a combination of measurement indices, including Quetelet's index, Broca index, and Corpulence index, to get a comprehensive understanding of the individual's body fat percentage and overall health risk.

**✓ Correct Answer: C. Sullivan’s index**