## **Core Concept**
The question tests understanding of embryonic development, specifically the role of trophoblasts. **Trophoblasts** are the outer layer of cells in a blastocyst, crucial for implantation and placenta formation. They differentiate into two layers: cytotrophoblasts and syncytiotrophoblasts.

## **Why the Correct Answer is Right**
The correct answer, **D. Placenta and chorionic villi**, is accurate because trophoblasts give rise to the placenta and chorionic villi. The trophoblast layer differentiates into **cytotrophoblasts** (inner layer) and **syncytiotrophoblasts** (outer layer). The syncytiotrophoblast invades the uterine lining, facilitating implantation, while cytotrophoblasts contribute to the formation of **chorionic villi**, which are essential for gas and nutrient exchange.

## **Why Each Wrong Option is Incorrect**
- **Option A:** This option is incorrect because trophoblasts do not directly give rise to the embryo proper; that role falls to the **inner cell mass**.
- **Option B:** This option is incorrect as trophoblasts do not form the **amnion**; the amnion develops from the epiblast (a part of the inner cell mass).
- **Option C:** This option is incorrect because while **extraembryonic membranes** are formed during embryonic development, the specific and direct derivatives of trophoblasts are more accurately described as the placenta and chorionic villi.

## **Clinical Pearl / High-Yield Fact**
A key point to remember is that **trophoblasts** are critical for the successful implantation of the embryo and the development of the **placenta**. Abnormalities in trophoblast function or invasion can lead to pregnancy complications such as preeclampsia or gestational trophoblastic disease.

## **Correct Answer:** D. Placenta and chorionic villi.