**Core Concept**
The placenta is a vital organ that develops in the uterus during pregnancy, playing a crucial role in providing oxygen and nutrients to the fetus and removing waste products. It is composed of several layers, each with distinct functions. The **decidua basalis** is one such layer.

**Why the Correct Answer is Right**
Although the question options are missing, typically, the layer that disappears at the end of pregnancy is related to the maternal-fetal interface. The **decidua basalis** is the layer of compact cells that forms the maternal component of the placenta. As pregnancy progresses and the placenta matures, certain components of the placenta undergo changes.

**Why Each Wrong Option is Incorrect**
**Option A:** Without the specific details of Option A, it's challenging to provide a precise explanation. However, incorrect options might include layers that do not disappear or are not directly related to the placental structure at the end of pregnancy.
**Option B:** Similarly, without specifics, if this option refers to a persistent layer of the placenta, it would be incorrect as it does not disappear.
**Option C:** If this option refers to a component that remains intact after pregnancy, it would not be the correct answer.
**Option D:** Assuming this is not the correct layer that disappears, it would be an incorrect choice due to its persistence or different role in placental function.

**Clinical Pearl / High-Yield Fact**
A key point to remember is that the placenta's structure and function are crucial for fetal development. Understanding which layers persist and which change or disappear can provide insights into placental function and potential complications.

**Correct Answer:** Correct Answer: D. Decidua basalis