## **Core Concept**
The question tests knowledge of viral structure, specifically focusing on viruses with a double-stranded RNA genome and a unique capsid composition. This requires understanding of virology, particularly the classification and structural features of viruses.

## **Why the Correct Answer is Right**
The correct answer, , refers to a virus known for having a double-stranded RNA genome enclosed by two distinct capsids. This description fits the characteristics of the Rotavirus. Rotaviruses are a common cause of severe diarrhea in infants and young children worldwide. They belong to the family Reoviridae. A key feature of rotaviruses is their genome, which consists of 11 segments of double-stranded RNA, and they have a triple-layered icosahedral capsid.

## **Why Each Wrong Option is Incorrect**
- **Option A:** This option is incorrect because it does not match the description of having a double-stranded RNA genome enclosed by two distinct capsids.
- **Option B:** This option is incorrect as it does not fit the specific structural characteristics mentioned in the question.
- **Option D:** This option is incorrect because it also does not align with the structural features of having two distinct capsids enclosing a double-stranded RNA genome.

## **Clinical Pearl / High-Yield Fact**
A memorable point for exams is that Rotavirus infections are a leading cause of severe gastroenteritis in children under 5 years of age worldwide. The introduction of the rotavirus vaccine has significantly reduced the incidence of severe rotavirus disease.

## **Correct Answer:** . Rotavirus