**Core Concept**
Vitamin A is an essential fat-soluble vitamin that plays a crucial role in maintaining vision, immune function, and skin health. It is also vital for the normal functioning of the retina and the integrity of the epithelial lining.

**Why the Correct Answer is Right**
The richest source of Vitamin A is liver, particularly the liver of animals such as beef, chicken, and fish. This is because Vitamin A is stored in the liver in the form of retinol and retinoic acid. The liver is the primary site of Vitamin A storage and recycling, making it the richest dietary source of this essential nutrient. Vitamin A is also found in smaller amounts in other animal products such as eggs, dairy, and fish, but the liver remains the richest source.

**Why Each Wrong Option is Incorrect**
* **Option A:** Not mentioned in the context of being the richest source of Vitamin A.
* **Option B:** While sweet potatoes are a good source of Vitamin A, they are not the richest source.
* **Option C:** Not a known rich source of Vitamin A.
* **Option D:** While carrots contain Vitamin A, they are not the richest source.

**Clinical Pearl / High-Yield Fact**
It is essential to note that Vitamin A deficiency can lead to night blindness, impaired immune function, and skin problems. The liver's ability to store and recycle Vitamin A makes it a vital organ for maintaining adequate Vitamin A levels in the body.

**Correct Answer:** C. Liver.