Choose the correct option regarding retrovirus

Options

A. An RNA virus that can synthesise DNA during infection
B. A DNA virus that can synthesise RNA during infection
C. A ssDNA virus
D. A dsRNA virus

Explanation

### Step-by-Step Solution:

1. **Understanding Retroviruses**: Retroviruses are a specific type of virus characterized by having RNA as their genetic material. This is a key feature that distinguishes them from other types of viruses.

2. **Key Enzyme - Reverse Transcriptase**: Retroviruses possess an enzyme called reverse transcriptase. This enzyme is crucial for the virus's ability to replicate. It allows the virus to convert its RNA genome into DNA.

3. **Process of Infection**: During the infection process, the retrovirus enters a host cell and utilizes reverse transcriptase to synthesize DNA from its RNA. This process effectively reverses the usual transcription process, where DNA is transcribed into RNA.

4. **Evaluating the Options**:
- **Option A**: "An RNA virus that can synthesize DNA during infections." This statement is true, as it accurately describes the nature of retroviruses.
- **Option B**: "A DNA virus that can synthesize RNA during infection." This is incorrect because retroviruses are RNA viruses, not DNA viruses.
- **Option C**: "A single-stranded DNA virus." This is also incorrect as retroviruses do not have DNA as their genetic material.
- **Option D**: "A double-stranded RNA virus." This is incorrect as well, as retroviruses have single-stranded RNA, not double-stranded RNA.

5. **Conclusion**: Based on the definitions and characteristics of retroviruses, the correct option is **Option A**: "An RNA virus that can synthesize DNA during infections."