Answer:
D. Capsid
Step-by-step explanation:
Nuclear membrane is lipid bilayer that is present in eukaryotic cells to protect the genome. Virus is a single cell that only replicates in the host cells. Viral genome (RNA or DNA) is either protected by capsid (protein shell) in case of non-enveloped viruses or both capsid proteins and lipid layer in case of enveloped viruses. Capsid is also responsible for the transfer and delivery of the genetic material from one viral cell to another. The mechanical properties of capsids vary in different virions that are responsible for DNA packaging and ejection strategies.