The operate activity has the primary responsibility for maintaining and monitoring digital products and supporting systems, so option C is correct. In ITIL, operate focuses on keeping live products and supporting environments functioning effectively. This includes monitoring system behavior, managing events, maintaining performance, ensuring reliability, and responding to deviations that affect product operation. Deliver is about providing services to users, including onboarding and service-level fulfillment. Support helps minimize the impact of incidents, issues, and disasters on users and services. Transition introduces new or changed products and services into the live environment. Operate is therefore the activity most closely associated with ongoing product health and technical stability. It provides the operational foundation that allows services to be delivered consistently and value to continue flowing.