What is the full form of $ARC$?

Human immune deficiency virus $(HIV)$ is a retrovirus with centrally located two $ssRNA$ molecules. It is covered by an outer layer of $I$ protein and an inner layer made up of $II$ protein.

The cause of $AIDS$ is ..........

After entering the body,which cell does $HIV$ primarily infect?

On which day is World $AIDS$ Day observed?

Which of the following diseases is both infectious and fatal?