A public library wants to implement a solution in which users need to connect to...

The correct choice is B. Captive portal . This is the common setup used in places like libraries, hotels, airports, and cafés. A user first joins the wireless network, opens a browser, and is redirected to a web page where they must log in, accept terms, or enter provided credentials. Since the question specifically mentions authentication through HTTPS , that matches the behavior of a captive portal very closely.

The other options do not line up with the scenario. WPA3 is a wireless encryption and authentication standard, but it is not the same as a browser-based login page after connection. Single sign-on and SAML are identity and federation technologies used to simplify authentication across applications or services, not to provide the typical guest Wi-Fi web login experience.

The important clue is the sequence described in the question: first connect to Wi-Fi, then authenticate through a web page. That is exactly how a captive portal works. In many public-access wireless environments, the portal sits between the client and normal internet access until the user successfully authenticates or accepts the usage policy. For Network+ exam purposes, browser-based guest wireless authentication is most directly associated with a captive portal .