In eukaryotic cell transcription, RNA splicing and RNA capping take place inside the
OR
Messenger RNA is produced in

Options

A. Ribosomes
B. Nucleus
C. Dictyosomes
D. ER

Answer

### Step-by-Step Solution:

1. **Understanding the Question**: The question asks where RNA splicing and RNA capping occur in a eukaryotic cell, and also where messenger RNA (mRNA) is produced.

2. **Transcription Process**: In eukaryotic cells, transcription is the process where DNA is used as a template to synthesize RNA. This process occurs in the nucleus of the cell.

3. **Formation of Heteronuclear RNA**: During transcription, the initial RNA produced is called heteronuclear RNA (hnRNA), which contains both introns (non-coding regions) and exons (coding regions).

4. **RNA Modifications**: Before hnRNA can be translated into proteins, it undergoes several modifications:
- **Splicing**: This is the process of removing introns and joining exons together to form a continuous coding sequence.
- **Capping**: A 5' cap is added to the beginning of the mRNA molecule, which is essential for stability and for the mRNA to be recognized by ribosomes during translation.
- **Tailing**: A poly-A tail is added to the 3' end of the mRNA, which also helps in stability and export from the nucleus.

5. **Final Product**: After these modifications, the mature mRNA is formed, which is ready to be transported out of the nucleus into the cytoplasm for translation.

6. **Conclusion**: Therefore, both RNA splicing and RNA capping take place inside the nucleus, and messenger RNA is produced in the nucleus as well.

### Answers:
- RNA splicing and RNA capping take place inside the **nucleus**.
- Messenger RNA is produced in the **nucleus**.