**Core Concept**
The question is testing the understanding of the different forms of DNA and their prevalence in the human body. **Supercoiled DNA**, **double-stranded DNA**, and **single-stranded DNA** are the three main forms of DNA, but only one is predominantly found in our body.

**Why the Correct Answer is Right**
The correct answer is **double-stranded DNA** because it is the most stable and compact form of DNA, suitable for storage and transmission of genetic information. This form of DNA is maintained in the nucleus of eukaryotic cells, including human cells, through the action of enzymes such as topoisomerase and DNA helicase. The double-stranded structure provides stability and protection to the genetic information, allowing for accurate replication and transcription.

**Why Each Wrong Option is Incorrect**
* **Option A:** Supercoiled DNA is a specific type of double-stranded DNA that is coiled upon itself, but it is not the predominant form of DNA in the human body.
* **Option B:** Single-stranded DNA is a form of DNA that is not suitable for storage and transmission of genetic information, as it is more prone to degradation and mutations.
* **Option D:** Linear DNA is a form of DNA that is not typically seen in the human body, as most DNA is organized into supercoiled or circular structures.

**Clinical Pearl / High-Yield Fact**
It's essential to remember that DNA is a stable molecule, but it can be damaged or mutated due to various factors such as radiation, chemicals, or errors during replication. Understanding the different forms of DNA and their stability is crucial for grasping genetic principles and their clinical applications.

**Correct Answer:** C.