Viral proteins and the genome of enveloped viruses in the host cell are assembled at:

Explanation

Among the given options, the correct site of viral assembly is the plasma membrane or the site of viral replication within the host cell. Ribosomes are important for synthesizing viral proteins but do not carry out assembly. The endoplasmic reticulum lumen plays a role in processing and glycosylating viral membrane proteins but is not the final assembly site. Mitochondria provide energy to the cell but are not directly involved in viral replication or assembly. Therefore, only Option A correctly identifies the site where viral proteins and the genome come together to form complete viral particles.