Detailed Explanation:
In ServiceNow, a change model defines how a change progresses through its lifecycle. The state model refers to the predefined states (e.g., New, Assess, Authorize) a change can transition through. State transitions are the movement between these states. Similarly, a phase model represents the different phases of the change process (such as Request, Authorization, Implementation), which can have distinct requirements and actions.
Each of these components defines a clear structure and sequence of events for managing changes effectively.

The Major Incident Management (MIM) workflow has specific role restrictions to ensure high-visibility issues are handled by authorized personnel.
* Proposing a Major Incident (C) is a function available to any user with the itil role. This allows technical staff to flag a critical issue they believe meets Major Incident criteria.
* Promoting (D) a candidate to a full Major Incident or Resolving (B) one requires the major_incident_manager role.
* Publishing updates (A) typically requires the communications_manager or major_incident_manager role.
Therefore, the ITIL user acts as the "eyes on the ground" who identifies and proposes potential major incidents for review.

ServiceNow Service Portfolio Management primarily manages Business Services and Application Services. A Business Service refers to services that support business processes or provide value to the customer, while Application Services are services provided by software applications. These services are tracked and managed to ensure they align with organizational objectives. Mobile Service and Technical Service are more specialized or less commonly grouped within the Service Portfolio scope.
Refer to Service Portfolio Management for further understanding.