Hardening focuses on reducing default attack surface and removing predictable access paths. Quentin Docter explains that default accounts are risky and highlights that Windows creates a Guest account that "represents a weakness that can be exploited," so you "should disable all accounts that are not needed, especially the Guest account." That directly supports option B .
Docter also emphasizes changing defaults as part of hardening: "Changing the default password to a complex password is also a good practice in hardening the device." That maps to option E (change the default administrator password). These actions reduce common credential-based attacks and limit unauthorized access.
Other options are either unrelated to workstation hardening (remote collaboration tools, virtual assistants) or weaken security (disabling screensavers may remove automatic lock behavior). Thus, the best two hardening steps are disable Guest and change the default admin password .