## **Core Concept**
Anaemia is a condition characterized by a decrease in the number of red blood cells or the amount of haemoglobin in the blood. The World Health Organization (WHO) provides criteria for defining anaemia based on age and sex. For children aged 5-11 years, a specific haemoglobin cutoff is used to diagnose anaemia.

## **Why the Correct Answer is Right**
The correct answer, **11.5 g/dL**, is based on the WHO criteria for diagnosing anaemia in children. According to the WHO, for children aged 5-11 years, a haemoglobin level less than **11.5 g/dL** is considered indicative of anaemia. This criterion helps in the early detection and management of anaemia in children, which is crucial for their growth and development.

## **Why Each Wrong Option is Incorrect**
* **Option A: 13 g/dL** - This is too high for the age group of 5-11 years. A haemoglobin level of 13 g/dL is generally considered within the normal range for older children and adults.
* **Option B: 12 g/dL** - Although close, this is not the specific cutoff recommended by the WHO for children aged 5-11 years.
* **Option D: 10.5 g/dL** - This is lower than the recommended cutoff and would misclassify some children with mild anaemia as not having the condition.

## **Clinical Pearl / High-Yield Fact**
A key point to remember is that the definition of anaemia varies by age, sex, and pregnancy status. For children, it's essential to use age-specific haemoglobin cutoffs for accurate diagnosis. The WHO criteria are widely used and provide a standardized approach to diagnosing anaemia globally.

## **Correct Answer: C. 11.5 g/dL.**