Web app architecture commonly includes which components?

• A. An FTP server and a mail server
• B. A web server and a backend database
• C. A DHCP server and a DNS server
• D. A desktop app and a local database

Answer: (B)

The main idea being tested is what core components a typical web application relies on. A web app is built to respond to user requests over the web, so it usually includes a web server that handles HTTP(S) requests and serves content, often delegating business logic to an application layer, and a backend database that stores and retrieves persistent data the app uses. This pairing—web server plus backend database—forms the foundation of most web architectures.

The other options don’t fit as the central web app structure. An FTP server and a mail server serve specialized functions (file transfer and email) that aren’t the standard components needed to run a web app. DHCP and DNS are network infrastructure services for IP assignment and name resolution, not the application layer of a web app. A desktop app with a local database describes a client-side desktop model rather than a web app architecture where clients access a central server over the web.