## Core Concept
The development of visual reflexes, such as the pupillary light reflex and accommodation reflex, involves the integration of afferent visual information from the retina to the brain and efferent signals to the muscles controlling pupil size and lens shape. This process matures early in life. **Visual reflexes** are primarily mediated through the **pretectal nuclei** and the **Edinger-Westphal nucleus**, which are parts of the midbrain.

## Why the Correct Answer is Right
The correct answer, **6 months**, indicates the age by which most visual reflexes are developed. At around 6 months of age, infants start to demonstrate more coordinated visual responses, including the **pupillary light reflex**, which is crucial for protecting the retina from excessive light and for adjusting to changes in luminance. This reflex involves the afferent pathway from the retina to the pretectal nuclei and the efferent pathway from the Edinger-Westphal nucleus to the ciliary muscles and iris sphincter.

## Why Each Wrong Option is Incorrect
- **Option A: 3 months** - While some basic visual reflexes may start to develop, 3 months might be too early for all visual reflexes to be fully developed and coordinated.
- **Option B: 9 months** - This is later than necessary for the basic development of visual reflexes; most are established earlier.
- **Option C: 12 months** - Similar to option B, this is later than required for the basic development of visual reflexes.

## Clinical Pearl / High-Yield Fact
A key clinical pearl is that the **absence or asymmetry of the pupillary light reflex** in infants can be an indicator of serious ocular or neurological abnormalities. Pediatricians often test this reflex during routine examinations. Remember, visual development and reflexes mature rapidly in the first few months of life.

## Correct Answer Line
**Correct Answer: D. 6 months.**