The central dogma is not applicable in the case cf`:`

Options

A. retroviruses
B. all prokaryotes
C. all animal viruses
D. all plant viruses

Explanation

**Step-by-Step Solution:**

1. **Understanding the Central Dogma**: The central dogma of molecular biology describes the flow of genetic information within a biological system. It is primarily a two-step process where DNA is transcribed into RNA, and then RNA is translated into proteins.

2. **Identifying the Steps**:
- **Transcription**: This is the first step where the information in DNA is copied into messenger RNA (mRNA).
- **Translation**: This is the second step where the mRNA is used as a template to synthesize proteins.

3. **Exploring Exceptions to the Central Dogma**: While the central dogma describes a general flow of information, there are exceptions where this flow does not occur as typically expected. One significant exception involves retroviruses.

4. **Analyzing the Options**:
- **Option A: Retrovirus**: Retroviruses have single-stranded RNA as their genetic material. They can reverse transcribe their RNA back into DNA using the enzyme reverse transcriptase. This process does not follow the traditional central dogma, making retroviruses an exception.
- **Option B: All Prokaryotes**: Prokaryotes generally follow the central dogma, so this option is incorrect.
- **Option C: All Animal Viruses**: Most animal viruses also follow the central dogma, so this option is incorrect.
- **Option D: All Plant Viruses**: Similar to animal viruses, most plant viruses adhere to the central dogma, making this option incorrect as well.

5. **Conclusion**: Based on the analysis, the correct answer is **Option A: Retrovirus**, as it represents a case where the central dogma is not applicable due to the reverse transcription process.