## **Core Concept**
The World Health Organization (WHO) provides criteria for diagnosing anemia based on hemoglobin (Hb) levels in different populations. Anemia is a condition characterized by a decrease in the number of red blood cells or the amount of hemoglobin in the blood, leading to insufficient oxygen delivery to tissues.

## **Why the Correct Answer is Right**
The correct cutoff for anemia in adult males as per WHO is hemoglobin less than 13 g/dL. This criterion is used globally to standardize the diagnosis of anemia. Hemoglobin levels can vary slightly between laboratories due to differences in measurement techniques, but 13 g/dL is the established threshold for adult men.

## **Why Each Wrong Option is Incorrect**
* **Option A:** This option is incorrect because it does not specify a value, making it impossible to assess its validity.
* **Option B:** This option is incorrect because it does not specify a value, making it impossible to assess its validity.
* **Option D:** This option suggests a value of 12 g/dL, which is actually the cutoff for adult women, not men.

## **Clinical Pearl / High-Yield Fact**
A key point to remember is that the WHO criteria for anemia are as follows: 13 g/dL for adult men, 12 g/dL for adult women, and 11 g/dL for pregnant women. These values are crucial for diagnosing and managing anemia in different populations.

## **Correct Answer:** . 13 g/dL.