**Core Concept**
The RNA primer is a short RNA sequence required for the initiation of DNA synthesis in eukaryotes. This primer is essential for the primase enzyme to add deoxyribonucleotides to the template strand, initiating the replication process.

**Why the Correct Answer is Right**
In eukaryotes, the RNA primer is formed by the primase enzyme, which is a type of RNA polymerase. The primase recognizes specific regions on the template strand called the origin of replication and adds short RNA primers, typically 10-13 nucleotides in length. These primers provide a free 3'-hydroxyl group for the DNA polymerase to add deoxyribonucleotides, allowing the replication process to begin.

**Why Each Wrong Option is Incorrect**
* **Option A:** This option is incorrect because it does not specify the correct enzyme responsible for forming the RNA primer in eukaryotes.
* **Option B:** This option is incorrect because it does not accurately describe the process of RNA primer formation in eukaryotes.
* **Option D:** This option is incorrect because it suggests an incorrect mechanism for RNA primer formation.

**Clinical Pearl / High-Yield Fact**
The RNA primer is essential for the initiation of DNA synthesis in eukaryotes, and its formation is catalyzed by the primase enzyme. A key point to remember is that the primase enzyme is specific to eukaryotes and is responsible for adding RNA primers to the template strand.

**Correct Answer: C. Primase enzyme.**