**Core Concept**
Congenital blindness refers to visual impairment present at birth or developing in the first few months of life. Causes are typically infectious, genetic, or developmental, involving direct damage to the retina, optic nerve, or visual pathways during fetal development.

**Why the Correct Answer is Right**
Vitamin A deficiency is a major cause of **xerophthalmia** and **corneal opacity**, but it primarily manifests as **infantile or early childhood blindness**, not congenital blindness. Congenital blindness arises from structural or developmental defects present at birth. Toxoplasmosis and congenital rubella are well-known teratogenic infections that cause retinal abnormalities and cataracts during fetal development. Cataracts, especially congenital cataracts, are a direct cause of blindness at birth due to lens opacity. Vitamin A deficiency, while severe, usually affects vision later in infancy or childhood, not at birth.

**Why Each Wrong Option is Incorrect**
Option A: Toxoplasmosis can cause retinal damage and blindness in the fetus when transmitted transplacentally, making it a recognized cause of congenital blindness.
Option B: Congenital rubella syndrome includes severe ocular abnormalities like cataracts and retinal dysplasia, leading to blindness at birth.
Option D: Congenital cataracts are a direct cause of blindness present at birth due to lens opacity in the fetal eye.

**Clinical Pearl / High-Yield Fact**
Remember: **Vitamin A deficiency causes blindness in infancy or early childhood**, not at birth. It is a preventable cause of vision loss, especially in developing countries, but is not a *congenital* cause. Always differentiate between *congenital* (present at birth) and *acquired* (developing after birth) blindness.

✓ Correct Answer: C. Vitamin A deficiency