Final answer:
Neuraminidase (Option B) is the protein associated with viral exit from the cell, as it facilitates the release of progeny viruses by cleaving sialic acid receptors on the host cell.
Step-by-step explanation:
The protein associated with viral exit from the cell is Neuraminidase (Option B). During the replication cycle of the influenza virus, hemagglutinin protein plays a role in the initial binding of the virus to the host cell's receptors, which are sialic acid complexes on the respiratory epithelial cells. The virus then enters the cell via endocytosis. After replication and the assembly of new virions, neuraminidase is the protein that facilitates the release of progeny viruses from the host cell by cleaving the sialic acid receptors. This cleavage prevents the newly formed virions from reattaching to the host cell, thus aiding in the spread of the virus.
The presence of neuraminidase on the surface of influenza virions is critical for their virulence. Influenza viruses are identified by their H (Hemagglutinin) and N (Neuraminidase) spikes, such as H1N1 or H3N2, indicating the variation of these proteins on the virus surface. Neuraminidase inhibitors, like oseltamivir and zanamivir, are examples of antiviral drugs that target the neuraminidase protein to prevent the virus from spreading.