Okay, let's tackle this question about the normal body mass index (BMI) range. First, I need to recall the standard BMI categories. From what I remember, BMI is calculated by dividing a person's weight in kilograms by the square of their height in meters. The categories are generally: underweight (below 18.5), normal weight (18.5–24.9), overweight (25–29.9), and obesity (30 and above).

The question asks for the normal range, so the correct answer should be 18.5 to 24.9. Now, the options aren't provided, but typical distractors might include ranges like 18.5–24.9 (correct), 20–25 (common misconception), 15–18.5 (underweight), or 25–30 (overweight).

For the core concept, the key is understanding BMI classification. The core concept here is the BMI categories established by the WHO. The correct answer is right because it aligns with the WHO's definition of normal weight. The incorrect options either fall into adjacent categories or use non-standard ranges.

When explaining each wrong option, I need to note that 18.5–24.9 is correct, so if an option is 18.5–24.5, that's incorrect. Similarly, 20–25 might be a trick option. The clinical pearl could be the exact WHO ranges and how they're used clinically. I should also mention that BMI is a general indicator and doesn't account for muscle mass or other factors. Finally, the correct answer is straightforward here.

**Core Concept**
Body Mass Index (BMI) categorizes weight status based on height and weight. The World Health Organization (WHO) defines normal BMI as **18.5–24.9 kg/m²**, reflecting a healthy weight range for most adults.

**Why the Correct Answer is Right**
A BMI of **18.5–24.9** corresponds to a balance between lean body mass and adipose tissue, minimizing risks of obesity-related diseases (e.g., diabetes, cardiovascular disease) and undernutrition. This range is derived from population studies linking it to optimal health outcomes and longevity.

**Why Each Wrong Option is Incorrect**
**Option A:** *15–18.5* is underweight, associated with malnutrition and immune dysfunction.
**Option B:** *25–30* is overweight/obese, increasing metabolic syndrome risk.
**Option C:** *10–15* is severe underweight, indicating cachexia or chronic illness.

**Clinical Pearl / High-Yield Fact**
Remember the **"18.5–24.9"** range as the WHO benchmark. Avoid confusion with "ideal weight" formulas, which are less evidence-based. Note that BMI does not account for muscle mass (e.g., athletes may have high BMI despite low body fat).

**Correct Answer: B. 18.5–24.9**

✓ Correct Answer: B. 18.5 - 24.9