## **Core Concept**
The conversion of **rhodopsin** to **retinal** and its regeneration is crucial for visual transduction. **Rhodopsin** is a protein found in the retina that is sensitive to light. It consists of **opsin** (a protein) and **11-cis retinal** (a derivative of vitamin A).

## **Why the Correct Answer is Right**
When light hits **rhodopsin**, the **11-cis retinal** undergoes isomerization to **all-trans retinal**. This change triggers a signal transduction cascade that ultimately leads to the perception of light. The enzyme **rhodopsin kinase** and **arrestin** are involved in the quenching of this signal. The correct answer, **retinal**, specifically refers to the conversion of **11-cis retinal** to **all-trans retinal** upon light exposure.

## **Why Each Wrong Option is Incorrect**
- **Option A:** This option is incorrect because it does not accurately represent the product of light converting **rhodopsin** or **retinene** (an older term for retinal).
- **Option B:** This option is incorrect as it does not accurately describe the conversion product related to **rhodopsin** and light exposure.
- **Option D:** This option is incorrect because it does not correctly identify the conversion product of **retinene** when exposed to light.

## **Clinical Pearl / High-Yield Fact**
A key point to remember is that **Vitamin A deficiency** can lead to night blindness due to impaired synthesis of **rhodopsin**. This highlights the importance of vitamin A in visual transduction.

## **Correct Answer:** .