Which of the following would trigger a process to take place?

The correct choice, an event, serves as a crucial trigger in various business processes. In the context of business change practice, an event can be understood as a specific occurrence or happening that instigates a response or a series of actions. For instance, events could include scenarios such as receiving a customer order, a change in market conditions, or an internal decision that all prompt certain processes to activate and unfold.

Events are essential in process management because they signify the beginning of an action or workflow, thus guiding how tasks are to be sequenced and managed. This dynamism allows organizations to be responsive and flexible in adapting to changes or new information, pivotal when aiming to achieve business objectives effectively.

While activities can be part of a process and functions describe what teams or individuals perform within that process, they do not inherently trigger actions. A reaction suggests a subsequent response to an action rather than being the initial cause that starts a process. Thus, the definitive characteristic of an event as a catalyst for processes makes it the correct choice in this context.