**B) RNA is distributed more widely in a cell**

1. **Introduction**
In a cell, various molecules are distributed to carry out different functions. DNA and RNA are nucleic acids that play essential roles in the storage and expression of genetic information. Chloroplasts and sphaerosomes are organelles found in specific cell types. Among these options, RNA is distributed more widely in a cell.

2. **DNA Distribution**
DNA is the genetic material present in the nucleus of eukaryotic cells and the nucleoid region of prokaryotic cells. It is also found in mitochondria and chloroplasts, which have their own DNA. However, DNA is confined to specific regions within the cell and is not distributed throughout the cytoplasm.

3. **Chloroplast Distribution**
Chloroplasts are organelles found in plant cells and some protists. They contain their own DNA, known as chloroplast DNA (cpDNA). While chloroplasts are distributed within the cell, their DNA is only present within the chloroplasts and not throughout the cytoplasm. Therefore, the distribution of chloroplasts and their DNA is limited to specific regions.

4. **Sphaerosome Distribution**
Sphaerosomes are lipid storage organelles found in plant cells. They are responsible for lipid metabolism and are primarily found in seeds and germinating tissues. Similar to chloroplasts, sphaerosomes are localized within specific cell types and are not distributed widely throughout the cytoplasm.

5. **RNA Distribution**
RNA is a nucleic acid that plays a crucial role in gene expression. Unlike DNA, RNA is present in both the nucleus and the cytoplasm of a cell. It is involved in various cellular processes, including transcription, translation, and protein synthesis. RNA molecules are distributed widely throughout the cytoplasm, allowing them to carry genetic information and participate in numerous cellular functions.

6. **Conclusion**
Among the given options, RNA is distributed more widely in a cell compared to DNA, chloroplasts, and sphaerosomes. RNA molecules are present in both the nucleus and cytoplasm, allowing them to participate in essential cellular processes.