Select ALL applications listed as requiring or commonly using reliable delivery through Transmission Control Protocol (TCP).

### Why this is right - **File transfers** is listed as an application that demands reliability because missing or disordered data can affect the transferred file. - **Email** is listed among applications that demand reliable delivery. - **Remote desktop** is listed among applications that demand reliable delivery. - **Secure Shell (SSH)** is listed among applications that demand reliable delivery. ### The concept TCP is suited to applications that need confirmation, sequencing, or retransmission of missing data. File transfers and interactive remote sessions are examples in the refresher. Real-time voice and multiplayer online games are listed as best-effort applications, where retransmission and confirmation may not be needed. User Datagram Protocol (UDP) has a smaller, simpler header and does not provide TCP's reliability features by itself. ### The other options - **B. Real-time voice**: The refresher lists this as a best-effort application, not as one that demands reliable delivery. It is tempting because voice communication is important, but the scenario may prioritize timely data over retransmission. - **E. Multiplayer online games**: The refresher lists these as best-effort applications. Missing data may be preferable to delaying newer real-time updates. ### Terms - **TCP**: Transmission Control Protocol. A transport protocol that supports reliable delivery through a session. - **SSH**: Secure Shell. A remote-access application listed as needing reliable delivery. - **UDP**: User Datagram Protocol. A transport protocol commonly used for best-effort applications. - **Reliable delivery**: Delivery supported by mechanisms such as acknowledgement and retransmission. - **Best-effort application**: An application that can operate without transport-level guarantees of delivery. ### Remember Use the application list to distinguish data that must be reliably delivered from real-time traffic that can tolerate loss.