Final answer:
In eukaryotic cells, most E) mRNAs are monocistronic, which means they code for a single polypeptide, unlike prokaryotic cells (bacteria and archaea), where mRNAs are often polycistronic.
Step-by-step explanation:
The question is asking in which groups are most messenger RNAs (mRNAs) monocistronic, meaning they code for only one polypeptide. In the world of cells, we can divide them into two main categories: prokaryotes and eukaryotes. Bacteria and archaea are classified as prokaryotes, which usually have polycistronic mRNAs, coding for multiple proteins.
On the other hand, eukarya, the domain of life that includes all animals, plants, fungi, and protists, typically have monocistronic mRNAs. Therefore, the correct answer to the question is eukarya (option C), as most mRNAs in eukaryotic cells are monocistronic.