**Core Concept**
Broca's index is a clinical measure used to assess the nutritional status of an individual, specifically in the context of Kwashiorkor, a form of severe malnutrition characterized by edema and muscle wasting. It is calculated based on the arm circumference and height of the individual, providing a simple and effective method for assessing malnutrition in field settings.

**Why the Correct Answer is Right**
The correct answer is calculated using the formula: Broca's index = (arm circumference in cm) / (height in cm) x 100. This ratio is then used to determine the nutritional status of the individual. A normal Broca's index value is between 18.5 and 23.5, with values below 18.5 indicating malnutrition. The arm circumference is a reliable indicator of muscle mass and fat stores, while the height is a reflection of overall growth and development.

**Why Each Wrong Option is Incorrect**
* **Option A:** This option is not a valid calculation for Broca's index, as it does not take into account the arm circumference and height of the individual.
* **Option B:** This option is incorrect because it does not provide a clear calculation or formula for Broca's index.
* **Option C:** This option is not relevant to the calculation of Broca's index, as it refers to a different clinical measure.

**Clinical Pearl / High-Yield Fact**
A key point to remember is that Broca's index is a quick and simple method for assessing malnutrition in field settings, but it should not be used as the sole indicator of nutritional status. A comprehensive assessment should include other clinical and laboratory parameters to confirm the diagnosis.

**Correct Answer: D. Broca's index = (arm circumference in cm) / (height in cm) x 100.**