**Core Concept**
Rotaviruses, Noroviruses, and Adenoviruses are common causes of viral gastroenteritis, characterized by the shedding of viruses in stool due to the destruction of the intestinal epithelial cells. This results in a significant loss of electrolytes, fluids, and nutrients.

**Why the Correct Answer is Right**
The primary mechanism of viral shedding in stool involves the attachment of viruses to the enterocytes, leading to their destruction and detachment from the intestinal wall. This process disrupts the normal barrier function of the intestinal epithelium, resulting in the loss of electrolytes and fluids. The Norovirus, in particular, is highly contagious and has a high replication rate in the gastrointestinal tract. The virus is shed in large quantities in the stool, making it a primary mode of transmission.

**Why Each Wrong Option is Incorrect**
* **Option A:** Rotavirus is indeed a common cause of viral gastroenteritis, but it is primarily shed in stool, making this option partially correct but not the best answer.
* **Option B:** Norovirus is the correct answer, as it is highly contagious and sheds large quantities of virus in the stool.
* **Option C:** Adenovirus can cause gastroenteritis, but it is not the primary mode of transmission through stool shedding.

**Clinical Pearl / High-Yield Fact**
The Norovirus is highly contagious and can spread through contaminated food, water, or direct contact with an infected person. It is essential to practice proper hand hygiene and maintain a clean environment to prevent the spread of Norovirus.

**Correct Answer:** B. Norovirus.