Service discovery aids account-driven User Enrollment. The iOS Deployment Reference states, "Account-driven User Enrollment uses service discovery to automatically locate the MDM enrollment URL, streamlining the process." Option A is false (Managed Apple ID required), C applies to ADE, and D is incorrect (federation is supported).
Reference:
iOS Deployment Reference, "Account-driven Enrollment" section.
Apple Platform Deployment Guide, "User Enrollment" section.