What best describes unplanned change that is also external?

The best option that describes unplanned change that is also external is divorce. Divorce is often a significant change that occurs due to factors outside the direct control of the individuals involved. It typically results from various external influences, such as marital discord, financial issues, or differing life goals, leading to a separation that can dramatically alter personal circumstances.

In contrast, personal growth involves changes that come from within an individual and is typically planned or self-directed, not external or unplanned. A life-changing event can encompass a wide range of occurrences but may not necessarily be classified as external, depending on the context. Crisis intervention refers to the actions taken to support individuals during a crisis but does not define a change itself—it's more about the response to an event rather than the event causing unplanned change. Thus, divorce is a more fitting description of the concept of unplanned change stemming from external situations.