How does ITIL define a 'critical incident'?

ITIL defines a 'critical incident' as an incident that results in significant disruption to the business. This classification emphasizes the substantial impact that certain incidents can have on organizational operations, potentially affecting critical services and processes. The focus is on the disruption's severity and its effects on business continuity, highlighting the necessity for urgent response and resolution. A critical incident typically requires immediate attention and may involve multiple stakeholders or complex issues to restore normal service operations.

The other options do not align with the definition of a critical incident because they either refer to minor issues that do not significantly affect business operations, or they describe situations that allow for delays without consequences, which directly contradicts the urgency that characterizes a critical incident. Additionally, incidents affecting a single user do not typically escalate to the level of being classified as critical unless they have broader implications, reinforcing the distinction that critical incidents are those that impact the organization on a larger scale.