## **Core Concept**
The question tests knowledge of the nutritional value of eggs, specifically their energy yield. Eggs are a common food item and a good source of various nutrients, including proteins, vitamins, and minerals. Understanding their caloric content is essential for dietary planning and management.

## **Why the Correct Answer is Right**
One large egg typically weighs about 50-60 grams and yields approximately 70 kcal of energy. This energy comes from the egg's components: the yolk and the white. The yolk contains fats and proteins, while the white is primarily protein. The caloric content can slightly vary based on the size of the egg, but 70 kcal is a commonly cited average.

## **Why Each Wrong Option is Incorrect**
- **Option A:** 10 kcal is significantly lower than the actual energy yield of an egg. This would not be a realistic caloric content for any standard-sized egg.
- **Option B:** 50 kcal is still lower than the actual caloric content of an average egg. While closer, it does not accurately represent the energy yield.
- **Option D:** 100 kcal is higher than the typical caloric content of a single large egg. This might be more representative of a larger egg or an egg with a higher fat content, but it's not the standard value.

## **Clinical Pearl / High-Yield Fact**
For dietary planning, especially in clinical settings or for patients with specific caloric needs, knowing that an egg provides about 70 kcal is crucial. This knowledge helps in calculating daily caloric intake and ensuring nutritional requirements are met.

## **Correct Answer:** C. 70.