Viruses are assigned to the kingdom ___ .

The correct option is C. None of the above.

1. One of the characteristics that five kingdom classification is based on, is cellular structure and organization.​
2. Viruses are acellular with only a protein coat that covers the internal genetic material of the virus.
3. Viruses show both living and nonliving characters under the presence and absence of a host respectively and non-living character is not present in organisms belonging to the five-kingdom classification system.
4. They lack cell organelles and cell membranes which are characteristics of eukaryotes and prokaryotes respectively.
5. The five-kingdom system of classification includes the prokaryotic Monera and the eukaryotic Protista, Fungi, Plantae, and Animalia.
6. Hence, viruses are not included in any of the 5 kingdoms.