**Core Concept**
Cardiac looping refers to the process of the heart tube's rotation and morphogenesis during embryonic development, resulting in the formation of the characteristic four-chambered heart structure. This process involves complex interactions between genetic and environmental factors, ultimately leading to the development of the cardiac chambers and their associated blood vessels.

**Why the Correct Answer is Right**
Cardiac looping begins around the 3rd week of gestation and is primarily driven by the left-right asymmetric expression of genes and proteins, such as Nodal and Pitx2. The looping process involves the rotation of the heart tube around its longitudinal axis, resulting in the formation of the right ventricle and the subsequent development of the left ventricle. This process is crucial for the proper alignment of the cardiac chambers and the establishment of a functional circulatory system.

**Why Each Wrong Option is Incorrect**
**Option A:** This is incorrect because cardiac looping is not solely dependent on neural crest cells, although they do play a role in the development of the cardiac conduction system and the outflow tracts.
**Option B:** This is incorrect because cardiac looping is not primarily driven by the formation of the neural tube or the development of the central nervous system.
**Option C:** This is incorrect because cardiac looping is not a result of the regression of the right ventricle, but rather its formation and subsequent development.

**Clinical Pearl / High-Yield Fact**
A key factor in the regulation of cardiac looping is the left-right asymmetric expression of genes, particularly Nodal and Pitx2. Understanding the molecular mechanisms underlying cardiac looping is essential for the diagnosis and treatment of congenital heart defects.

**Correct Answer:** C. Around the 3rd week of gestation.