**Core Concept**
The question is testing knowledge of congenital uterine anomalies, which are a group of developmental malformations of the uterus that can affect reproductive health. These anomalies can be classified based on the morphology of the uterus and the presence of septa or other anomalies.

**Why the Correct Answer is Right**
Uterus didelphys is a congenital anomaly where two separate uteruses develop from two separate Müllerian ducts. This anomaly is characterized by the presence of two distinct uteruses, each with its own cervix and sometimes separate vaginas. The presence of two separate uteruses can lead to complications such as recurrent miscarriages, preterm labor, and infertility.

**Why Each Wrong Option is Incorrect**
* **Option B:** Arcuate uterus is a mild form of Müllerian duct anomaly where the uterine cavity is slightly more pointed than normal. It is not considered a congenital abnormality of the uterus.
* **Option C:** Unicornuate uterus is a rare congenital anomaly where one Müllerian duct fails to develop, resulting in a single, smaller uterus. While it is a congenital anomaly, it is not the correct answer.
* **Option D:** Septate uterus is a congenital anomaly where a septum (a wall of tissue) separates the uterine cavity. While it is a congenital anomaly, it is not the correct answer.

**Clinical Pearl / High-Yield Fact**
When evaluating a patient with recurrent miscarriages or infertility, it's essential to consider congenital uterine anomalies as a potential cause. A thorough ultrasound examination can help diagnose these anomalies, and hysteroscopy may be necessary for further evaluation.

**Correct Answer:** A. Uterus didelphys