## Core Concept
The congenital rubella syndrome (CRS) is a condition that results from rubella virus infection during pregnancy, leading to a variety of birth defects. The classical triad of CRS includes features that are commonly observed in affected infants.

## Why the Correct Answer is Right
The classical triad for congenital rubella syndrome consists of:
- **Cataracts**: Due to the virus's teratogenic effects on the developing lens of the eye.
- **Heart defects**: Such as patent ductus arteriosus, pulmonary artery stenosis, and tetralogy of Fallot, resulting from disrupted cardiac development.
- **Deafness**: Caused by damage to the developing inner ear structures.

## Why Each Wrong Option is Incorrect
- **Option A:** Cataracts are a well-recognized component of the classical triad.
- **Option B:** Heart defects are another key feature of the classical triad.
- **Option D:** Deafness is also a critical component of the classical triad.

## Clinical Pearl / High-Yield Fact
A key clinical pearl is that the classical triad of congenital rubella syndrome includes cataracts, heart defects, and deafness. Additionally, other manifestations can include microcephaly, intellectual disability, and diabetes mellitus. The prevention of CRS through vaccination is a critical public health measure.

## Correct Answer: B.