What best defines an Incident?

An incident is best defined as an unplanned interruption to or quality reduction of an IT service because it highlights the nature of incidents as unexpected events that negatively impact service delivery. This definition captures the essence of what constitutes an incident—namely, that it disrupts normal service operation or diminishes service quality, affecting end-users or business processes.

By focusing on the "unplanned" aspect, it is clear that incidents are not scheduled maintenance or predictable problems but rather unexpected issues that require immediate attention to restore service functionality. This aligns with ITSM practices that emphasize quick resolution to minimize disruption.

The other options do not accurately reflect the core definition of an incident. For instance, an unplanned increase in service availability does not represent a disruption but rather an enhancement, and a predicted service outage relates to planned activities, which fall outside the realm of what constitutes an incident. Additionally, simply processing any service request lacks the specificity needed to define an incident; service requests can range from inquiries to enhancements and are not inherently disruptive events. Thus, option B provides the most precise definition aligned with ITSM principles.