Which of the following is NOT a common type of server?

• A. Database server
• B. Network server
• C. Web server
• D. File server

Answer: (A)

Understanding servers by the service they provide helps you see why this choice stands out. Web servers, file servers, and network servers are the classic, frequently listed categories because they deliver visible, everyday functions to users: hosting websites, sharing files, and handling core network services. A database server, while very common in real networks, is a specialized back-end service—it's the machine (or software) running a database management system to store and retrieve data for applications. In some teaching contexts, that kind of backend database service isn’t treated as a separate “type of server” in the same way as web, file, or network servers, so it’s labeled as not a common type of server in that framing.