Final answer:
Norovirus, part of the Calicivirus family, is an RNA virus that has a non-enveloped structure with glycoproteins that aid in attaching to host cells(option b).
Step-by-step explanation:
The Calicivirus, also known as Norovirus, is a type of b) RNA virus.
This is in contrast to DNA viruses, retroviruses, or other infectious agents without nucleic acids. Noroviruses are non-enveloped viruses comprised of a protein shell called a capsid, which encapsulates their RNA genetic material. Regarding general virus structure, it's important to note that not all viruses are encased in a membrane; some are non-enveloped like Caliciviruses.
When discussing life, viruses, including Caliciviruses, are not considered living because they are acellular and lack the various components required for life, such as ribosomes and metabolic processes. They are merely genetic material surrounded by a protein coat, and they need to hijack a host cell's machinery to replicate. Finally, scientists classify viruses into families based on their structures, such as RNA or DNA genome, and whether their capsids are icosahedral or helical. Given that Noroviruses have an RNA genome and icosahedral capsid structure, they are classified differently from viruses with a helical capsid.