**Core Concept**
The placenta is a vital organ that develops in the uterus during pregnancy, providing oxygen and nutrients to the fetus while removing waste products. The fetal-maternal interface is a complex structure that involves the interaction of various cell types and tissues.

**Why the Correct Answer is Right**
The fetal side of the mature placenta is covered by a layer of cells known as the chorionic plate, which is a continuation of the chorion, a membranous structure that surrounds the embryo. The chorionic plate is a thin, avascular layer that separates the fetal blood vessels from the maternal blood spaces. This layer is essential for maintaining the integrity of the fetal-maternal interface and preventing the exchange of maternal immune cells with the fetus.

**Why Each Wrong Option is Incorrect**
**Option A:** This option is incorrect because the chorionic plate is not a layer of connective tissue, but rather a thin layer of epithelial cells.

**Option B:** This option is incorrect because the basal plate is a layer of cells on the maternal side of the placenta, not the fetal side.

**Option C:** This option is incorrect because the amnion is a membrane that surrounds the fetus, but it is not a layer of cells that covers the fetal side of the placenta.

**Clinical Pearl / High-Yield Fact**
The chorionic plate is an essential structure that plays a crucial role in maintaining the integrity of the fetal-maternal interface. It is a key component of the placental structure that allows for the exchange of gases, nutrients, and waste products between the fetus and the mother.

**Correct Answer: B. Basal plate**