## **Core Concept**
Soya bean, also known as soybean, is a legume that is rich in various nutrients, particularly **protein** and **isoflavones**. It is a versatile food source that provides a significant amount of essential amino acids, making it an excellent option for vegetarians and vegans.

## **Why the Correct Answer is Right**
The correct answer, **. (Isoflavones)**, is right because soya beans are exceptionally rich in isoflavones, which are a type of phytoestrogen. Isoflavones have been studied for their potential health benefits, including reducing the risk of heart disease and certain cancers. Soya beans contain a high amount of isoflavones compared to other foods.

## **Why Each Wrong Option is Incorrect**
- **Option A:** While soya beans do contain some amount of carbohydrates, they are not particularly noted for being rich in them compared to their content of protein and isoflavones.
- **Option B:** Soya beans are indeed a good source of protein but stating they are rich in protein without specifying isoflavones makes this option less specific and incorrect given the context of the question.
- **Option C:** There is no commonly recognized nutrient or compound listed here that soya beans are specifically known for being rich in, making it an incorrect option.

## **Clinical Pearl / High-Yield Fact**
A memorable point for students to recall is that **soya beans are a rich source of isoflavones**, which can have both beneficial and adverse effects depending on the context of consumption, such as influencing hormone-sensitive cancers or thyroid function.

## **Correct Answer Line**
**Correct Answer: D. Isoflavones**