**Core Concept**
The question is testing the understanding of the process of DNA replication using an RNA template, which is a key concept in molecular biology. This process is known as reverse transcription, and it is a crucial mechanism in the life cycle of retroviruses.

**Why the Correct Answer is Right**
The correct answer is based on the enzyme responsible for this process, which is Reverse Transcriptase (RT). RT is an RNA-dependent DNA polymerase that synthesizes a complementary DNA (cDNA) strand from an RNA template. This enzyme is essential for the replication of retroviruses, such as HIV, and is also used in various molecular biology techniques, including PCR and cDNA synthesis. During reverse transcription, RT reads the RNA template and matches the incoming nucleotides to the base pairing rules of DNA, forming a complementary DNA strand.

**Why Each Wrong Option is Incorrect**
**Option A:** This option is incorrect because DNA polymerase I is an enzyme involved in DNA replication and repair, but it is not responsible for reverse transcription.
**Option B:** This option is incorrect because DNA polymerase II is involved in DNA replication, but it is not involved in reverse transcription.
**Option C:** This option is incorrect because RNA polymerase is involved in transcription, the process of synthesizing RNA from a DNA template, but it is not involved in reverse transcription.

**Clinical Pearl / High-Yield Fact**
One key point to remember is that reverse transcription is a unique process that involves the synthesis of DNA from an RNA template, which is essential for the replication of retroviruses. This process is distinct from DNA replication and transcription, and it has important implications for our understanding of viral biology and the development of antiviral therapies.

**Correct Answer: A. Reverse Transcriptase**