To design a solution that meets the backup and replication requirements for Veeam University Hospital, you need to consider some of the components that are needed for the on-premises design. This will help you to ensure the performance and reliability of the backup and replication operations, as well as the scalability and manageability of the backup infrastructure.

According to the Veeam Backup & Replication Best Practice Guide1, some of the components that are needed for the on-premises design are:

* Backup server. This is the core component of Veeam Backup & Replication that controls and coordinates backups, replication, recovery verification, and restore tasks. It also manages backup infrastructure components, such as proxy servers, repository servers, WAN accelerators, etc. You need to have a backup server at each site, as recommended by the best practice guide2.

* Backup proxy. This is a component that retrieves data from the source host, processes it and transfers to the backup repository. It also performs data compression, deduplication, encryption, etc. You need to have at least one backup proxy at each site, as recommended by the best practice guide3.

* Backup repository. This is a server where Veeam Backup & Replication keeps backup files, backup copies and metadata of replicated VMs. It can be a Windows or Linux server, a NAS device, a deduplication appliance, etc. You need to have at least one backup repository at each site, as recommended by the best practice guide4.

* Mount server. This is a component that mounts backup files from the backup repository to the backup proxy during restore operations. It also performs data decompression, deduplication, decryption, etc. You need to have a mount server at each site where you plan to perform restores, as recommended by the best practice guide5.

* Gateway server. This is a component that acts as a data mover between the backup proxy and the backup repository when they are located in different sites or networks. It also performs data encryption and decryption for secure data transfer. You need to have a gateway server at each site where you have a backup repository that is accessed by a remote backup proxy, as recommended by the best practice guide.

Therefore, based on these components, the answer that describes which components are needed for the on-premises design is D. Backup server, backup proxy, backup repository, mount server, gateway server.