**Core Concept**
The conus cordis is a critical region in the embryonic heart, responsible for the separation of the outflow tracts and the formation of the ventricular septum. Unequal division of the conus cordis can lead to various congenital heart defects.

**Why the Correct Answer is Right**
The correct answer results from an abnormal anterior displacement of the conotruncal septum, which disrupts the normal separation of the outflow tracts. This anomaly affects the development of the pulmonary artery and aortic arch, leading to a characteristic cardiac defect. The conotruncal septum plays a crucial role in the formation of the ventricular outflow tracts, and its abnormal displacement can result in a specific congenital heart defect.

**Why Each Wrong Option is Incorrect**
* **Option A:** This option is incorrect because it does not accurately describe the cardiac defect resulting from unequal division of the conus cordis.
* **Option B:** This option is incorrect because it refers to a different cardiac anomaly, unrelated to the conus cordis.
* **Option C:** This option is incorrect because it describes a cardiac defect that results from a different embryonic developmental issue.

**Clinical Pearl / High-Yield Fact**
The conotruncal septum is a critical structure in the embryonic heart, and its abnormal development can lead to various congenital heart defects, including tetralogy of Fallot and persistent truncus arteriosus.

**Correct Answer: A. Transposition of the great arteries.**