**Core Concept**
Eunuchs are individuals who have undergone surgical castration, resulting in a significant reduction of sex hormones, particularly testosterone. This condition can be caused by various factors, including genetic disorders, trauma, or intentional surgical procedures. The Hijras and Zenanas are two distinct groups of eunuchs with unique cultural and historical backgrounds.

**Why the Correct Answer is Right**
The Hijras are a group of eunuchs from South Asia, particularly from India and Pakistan, who undergo a traditional initiation ceremony, known as "Nirvan," which involves the removal of the penis and scrotum before puberty. This procedure is performed to prevent the development of secondary sex characteristics and to create a sense of androgyny. In contrast, the Zenanas are a group of eunuchs from Southeast Asia, particularly from Thailand and Indonesia, who are often castrated as adults and retain their external genitalia.

**Why Each Wrong Option is Incorrect**
* **Option A:** This option is incorrect because it does not specify the correct group of eunuchs. The Hijras are the ones who undergo the removal of the penis and scrotum before puberty.
* **Option B:** This option is incorrect because the Zenanas are a group of eunuchs who retain their external genitalia, unlike the Hijras.
* **Option C:** This option is incorrect because it does not accurately describe the traditional initiation ceremony of the Hijras or the characteristics of the Zenanas.
* **Option D:** This option is incorrect because it does not provide a clear or accurate description of the eunuchs.

**Clinical Pearl / High-Yield Fact**
It is essential to note that the Hijras and Zenanas are two distinct groups of eunuchs with unique cultural and historical backgrounds. Understanding their differences is crucial for providing appropriate medical care and support.

**Correct Answer:** B. Genitalia of Zenanas are intact.